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http://rosettacode.org/wiki/Permutations_by_swapping
Permutations by swapping
Task Generate permutations of n items in which successive permutations differ from each other by the swapping of any two items. Also generate the sign of the permutation which is +1 when the permutation is generated from an even number of swaps from the initial state, and -1 for odd. Show the permutations and signs of three items, in order of generation here. Such data are of use in generating the determinant of a square matrix and any functions created should bear this in mind. Note: The Steinhaus–Johnson–Trotter algorithm generates successive permutations where adjacent items are swapped, but from this discussion adjacency is not a requirement. References Steinhaus–Johnson–Trotter algorithm Johnson-Trotter Algorithm Listing All Permutations Heap's algorithm [1] Tintinnalogia Related tasks   Matrix arithmetic   Gray code
#Clojure
Clojure
  (defn permutation-swaps "List of swap indexes to generate all permutations of n elements" [n] (if (= n 2) `((0 1)) (let [old-swaps (permutation-swaps (dec n)) swaps-> (partition 2 1 (range n)) swaps<- (reverse swaps->)] (mapcat (fn [old-swap side] (case side  :first swaps<-  :right (conj swaps<- old-swap)  :left (conj swaps-> (map inc old-swap)))) (conj old-swaps nil) (cons :first (cycle '(:left :right)))))))     (defn swap [v [i j]] (-> v (assoc i (nth v j)) (assoc j (nth v i))))     (defn permutations [n] (let [permutations (reduce (fn [all-perms new-swap] (conj all-perms (swap (last all-perms) new-swap))) (vector (vec (range n))) (permutation-swaps n)) output (map vector permutations (cycle '(1 -1)))] output))     (doseq [n [2 3 4]] (dorun (map println (permutations n))))  
http://rosettacode.org/wiki/Permutation_test
Permutation test
Permutation test You are encouraged to solve this task according to the task description, using any language you may know. A new medical treatment was tested on a population of n + m {\displaystyle n+m} volunteers, with each volunteer randomly assigned either to a group of n {\displaystyle n} treatment subjects, or to a group of m {\displaystyle m} control subjects. Members of the treatment group were given the treatment, and members of the control group were given a placebo. The effect of the treatment or placebo on each volunteer was measured and reported in this table. Table of experimental results Treatment group Control group 85 68 88 41 75 10 66 49 25 16 29 65 83 32 39 92 97 28 98 Write a program that performs a permutation test to judge whether the treatment had a significantly stronger effect than the placebo. Do this by considering every possible alternative assignment from the same pool of volunteers to a treatment group of size n {\displaystyle n} and a control group of size m {\displaystyle m} (i.e., the same group sizes used in the actual experiment but with the group members chosen differently), while assuming that each volunteer's effect remains constant regardless. Note that the number of alternatives will be the binomial coefficient ( n + m n ) {\displaystyle {\tbinom {n+m}{n}}} . Compute the mean effect for each group and the difference in means between the groups in every case by subtracting the mean of the control group from the mean of the treatment group. Report the percentage of alternative groupings for which the difference in means is less or equal to the actual experimentally observed difference in means, and the percentage for which it is greater. Note that they should sum to 100%. Extremely dissimilar values are evidence of an effect not entirely due to chance, but your program need not draw any conclusions. You may assume the experimental data are known at compile time if that's easier than loading them at run time. Test your solution on the data given above.
#Delphi
Delphi
  program Permutation_test;   {$APPTYPE CONSOLE}   uses System.SysUtils;   procedure Comb(n, m: Integer; emit: TProc<TArray<Integer>>); var s: TArray<Integer>; last: Integer;   procedure rc(i, next: Integer); begin for var j := next to n - 1 do begin s[i] := j; if i = last then emit(s) else rc(i + 1, j + 1); end; end;   begin SetLength(s, m); last := m - 1; rc(0, 0); end;   begin var tr: TArray<Integer> := [85, 88, 75, 66, 25, 29, 83, 39, 97]; var ct: TArray<Integer> := [68, 41, 10, 49, 16, 65, 32, 92, 28, 98];   // collect all results in a single list var all: TArray<Integer> := concat(tr, ct);   // compute sum of all data, useful as intermediate result var sumAll := 0; for var r in all do inc(sumAll, r);   // closure for computing scaled difference. // compute results scaled by len(tr)*len(ct). // this allows all math to be done in integers. var sd := function(trc: TArray<Integer>): Integer begin var sumTr := 0; for var x in trc do inc(sumTr, all[x]); result := sumTr * length(ct) - (sumAll - sumTr) * length(tr); end;   // compute observed difference, as an intermediate result var a: TArray<Integer>; SetLength(a, length(tr)); for var i := 0 to High(a) do a[i] := i;   var sdObs := sd(a);   // iterate over all combinations. for each, compute (scaled) // difference and tally whether leq or gt observed difference. var nLe, nGt: Integer;   comb(length(all), length(tr), procedure(c: TArray<Integer>) begin if sd(c) > sdObs then inc(nGt) else inc(nle); end);   // print results as percentage var pc := 100 / (nLe + nGt); writeln(format('differences <= observed: %f%%', [nle * pc])); writeln(format('differences > observed: %f%%', [ngt * pc]));   {$IFNDEF UNIX} readln; {$ENDIF} end.
http://rosettacode.org/wiki/Perlin_noise
Perlin noise
The   Perlin noise   is a kind of   gradient noise   invented by   Ken Perlin   around the end of the twentieth century and still currently heavily used in   computer graphics,   most notably to procedurally generate textures or heightmaps. The Perlin noise is basically a   pseudo-random   mapping of   R d {\displaystyle \mathbb {R} ^{d}}   into   R {\displaystyle \mathbb {R} }   with an integer   d {\displaystyle d}   which can be arbitrarily large but which is usually   2,   3,   or   4. Either by using a dedicated library or by implementing the algorithm, show that the Perlin noise   (as defined in 2002 in the Java implementation below)   of the point in 3D-space with coordinates     3.14,   42,   7     is     0.13691995878400012. Note: this result assumes 64 bit IEEE-754 floating point calculations. If your language uses a different floating point representation, make a note of it and calculate the value accurate to 15 decimal places, or your languages accuracy threshold if it is less. Trailing zeros need not be displayed.
#C
C
  #include<stdlib.h> #include<stdio.h> #include<math.h>   int p[512];   double fade(double t) { return t * t * t * (t * (t * 6 - 15) + 10); } double lerp(double t, double a, double b) { return a + t * (b - a); } double grad(int hash, double x, double y, double z) { int h = hash & 15; double u = h<8 ? x : y, v = h<4 ? y : h==12||h==14 ? x : z; return ((h&1) == 0 ? u : -u) + ((h&2) == 0 ? v : -v); }   double noise(double x, double y, double z) { int X = (int)floor(x) & 255, Y = (int)floor(y) & 255, Z = (int)floor(z) & 255; x -= floor(x); y -= floor(y); z -= floor(z); double u = fade(x), v = fade(y), w = fade(z); int A = p[X ]+Y, AA = p[A]+Z, AB = p[A+1]+Z, B = p[X+1]+Y, BA = p[B]+Z, BB = p[B+1]+Z;   return lerp(w, lerp(v, lerp(u, grad(p[AA ], x , y , z ), grad(p[BA ], x-1, y , z )), lerp(u, grad(p[AB ], x , y-1, z ), grad(p[BB ], x-1, y-1, z ))), lerp(v, lerp(u, grad(p[AA+1], x , y , z-1 ), grad(p[BA+1], x-1, y , z-1 )), lerp(u, grad(p[AB+1], x , y-1, z-1 ), grad(p[BB+1], x-1, y-1, z-1 )))); }   void loadPermutation(char* fileName){ FILE* fp = fopen(fileName,"r"); int permutation[256],i;   for(i=0;i<256;i++) fscanf(fp,"%d",&permutation[i]);   fclose(fp);   for (int i=0; i < 256 ; i++) p[256+i] = p[i] = permutation[i]; }   int main(int argC,char* argV[]) { if(argC!=5) printf("Usage : %s <permutation data file> <x,y,z co-ordinates separated by space>"); else{ loadPermutation(argV[1]); printf("Perlin Noise for (%s,%s,%s) is %.17lf",argV[2],argV[3],argV[4],noise(strtod(argV[2],NULL),strtod(argV[3],NULL),strtod(argV[4],NULL))); }   return 0; }  
http://rosettacode.org/wiki/Perfect_totient_numbers
Perfect totient numbers
Generate and show here, the first twenty Perfect totient numbers. Related task   Totient function Also see   the OEIS entry for   perfect totient numbers.   mrob   list of the first 54
#ARM_Assembly
ARM Assembly
  /* ARM assembly Raspberry PI or android with termux */ /* program totientPerfect.s */   /* REMARK 1 : this program use routines in a include file see task Include a file language arm assembly for the routine affichageMess conversion10 see at end of this program the instruction include */ /* for constantes see task include a file in arm assembly */ /************************************/ /* Constantes */ /************************************/ .include "../constantes.inc" .equ MAXI, 20   /*********************************/ /* Initialized data */ /*********************************/ .data szMessNumber: .asciz " @ " szCarriageReturn: .asciz "\n"   /*********************************/ /* UnInitialized data */ /*********************************/ .bss sZoneConv: .skip 24 /*********************************/ /* code section */ /*********************************/ .text .global main main: mov r4,#2 @ start number mov r6,#0 @ line counter mov r7,#0 @ result counter 1: mov r0,r4 mov r5,#0 @ totient sum 2: bl totient @ compute totient add r5,r5,r0 @ add totient cmp r0,#1 beq 3f b 2b 3: cmp r5,r4 @ compare number and totient sum bne 4f mov r0,r4 @ display result if equals ldr r1,iAdrsZoneConv bl conversion10 @ call décimal conversion ldr r0,iAdrszMessNumber ldr r1,iAdrsZoneConv @ insert conversion in message bl strInsertAtCharInc bl affichageMess @ display message add r7,r7,#1 add r6,r6,#1 @ increment indice line display cmp r6,#5 @ if = 5 new line bne 4f mov r6,#0 ldr r0,iAdrszCarriageReturn bl affichageMess 4: add r4,r4,#1 @ increment number cmp r7,#MAXI @ maxi ? blt 1b @ and loop   ldr r0,iAdrszCarriageReturn bl affichageMess   100: @ standard end of the program mov r0, #0 @ return code mov r7, #EXIT @ request to exit program svc #0 @ perform the system call iAdrszCarriageReturn: .int szCarriageReturn iAdrsZoneConv: .int sZoneConv iAdrszMessNumber: .int szMessNumber /******************************************************************/ /* compute totient of number */ /******************************************************************/ /* r0 contains number */ totient: push {r1-r5,lr} @ save registers mov r4,r0 @ totient mov r5,r0 @ save number mov r1,#0 @ for first divisor 1: @ begin loop mul r3,r1,r1 @ compute square cmp r3,r5 @ compare number bgt 4f @ end add r1,r1,#2 @ next divisor mov r0,r5 bl division cmp r3,#0 @ remainder null ? bne 3f 2: @ begin loop 2 mov r0,r5 bl division cmp r3,#0 moveq r5,r2 @ new value = quotient beq 2b   mov r0,r4 @ totient bl division sub r4,r4,r2 @ compute new totient 3: cmp r1,#2 @ first divisor ? moveq r1,#1 @ divisor = 1 b 1b @ and loop 4: cmp r5,#1 @ final value > 1 ble 5f mov r0,r4 @ totient mov r1,r5 @ divide by value bl division sub r4,r4,r2 @ compute new totient 5: mov r0,r4 100: pop {r1-r5,pc} @ restaur registers   /***************************************************/ /* ROUTINES INCLUDE */ /***************************************************/ .include "../affichage.inc"  
http://rosettacode.org/wiki/Playing_cards
Playing cards
Task Create a data structure and the associated methods to define and manipulate a deck of   playing cards. The deck should contain 52 unique cards. The methods must include the ability to:   make a new deck   shuffle (randomize) the deck   deal from the deck   print the current contents of a deck Each card must have a pip value and a suit value which constitute the unique value of the card. Related tasks: Card shuffles Deal cards_for_FreeCell War Card_Game Poker hand_analyser Go Fish
#CoffeeScript
CoffeeScript
#translated from JavaScript example class Card constructor: (@pip, @suit) ->   toString: => "#{@pip}#{@suit}"   class Deck pips = '2 3 4 5 6 7 8 9 10 J Q K A'.split ' ' suits = '♣ ♥ ♠ ♦'.split ' '   constructor: (@cards) -> if not @cards? @cards = [] for suit in suits for pip in pips @cards.push new Card(pip, suit)   toString: => "[#{@cards.join(', ')}]"   shuffle: => for card, i in @cards randomCard = parseInt @cards.length * Math.random() @cards[i] = @cards.splice(randomCard, 1, card)[0]   deal: -> @cards.shift()
http://rosettacode.org/wiki/Pi
Pi
Create a program to continually calculate and output the next decimal digit of   π {\displaystyle \pi }   (pi). The program should continue forever (until it is aborted by the user) calculating and outputting each decimal digit in succession. The output should be a decimal sequence beginning   3.14159265 ... Note: this task is about   calculating   pi.   For information on built-in pi constants see Real constants and functions. Related Task Arithmetic-geometric mean/Calculate Pi
#C.2B.2B
C++
#include <iostream> #include <boost/multiprecision/cpp_int.hpp>   using namespace boost::multiprecision;   class Gospers { cpp_int q, r, t, i, n;   public:   // use Gibbons spigot algorith based on the Gospers series Gospers() : q{1}, r{0}, t{1}, i{1} { ++*this; // move to the first digit }   // the ++ prefix operator will move to the next digit Gospers& operator++() { n = (q*(27*i-12)+5*r) / (5*t);   while(n != (q*(675*i-216)+125*r)/(125*t)) { r = 3*(3*i+1)*(3*i+2)*((5*i-2)*q+r); q = i*(2*i-1)*q; t = 3*(3*i+1)*(3*i+2)*t; i++;   n = (q*(27*i-12)+5*r) / (5*t); }   q = 10*q; r = 10*r-10*n*t;   return *this; }   // the dereference operator will give the current digit int operator*() { return (int)n; } };   int main() { Gospers g;   std::cout << *g << "."; // print the first digit and the decimal point   for(;;) // run forever { std::cout << *++g; // increment to the next digit and print } }
http://rosettacode.org/wiki/Periodic_table
Periodic table
Task Display the row and column in the periodic table of the given atomic number. The periodic table Let us consider the following periodic table representation. __________________________________________________________________________ | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | | | |1 H He | | | |2 Li Be B C N O F Ne | | | |3 Na Mg Al Si P S Cl Ar | | | |4 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr | | | |5 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe | | | |6 Cs Ba * Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn | | | |7 Fr Ra ° Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og | |__________________________________________________________________________| | | | | |8 Lantanoidi* La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu | | | |9 Aktinoidi° Ak Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr | |__________________________________________________________________________| Example test cases;   1 -> 1 1   2 -> 1 18   29 -> 4 11   42 -> 5 6   57 -> 8 4   58 -> 8 5   72 -> 6 4   89 -> 9 4 Details; The representation of the periodic table may be represented in various way. The one presented in this challenge does have the following property : Lantanides and Aktinoides are all in a dedicated row, hence there is no element that is placed at 6, 3 nor 7, 3. You may take a look at the atomic number repartitions here. The atomic number is at least 1, at most 118. See also   the periodic table   This task was an idea from CompSciFact   The periodic table in ascii that was used as template
#FutureBasic
FutureBasic
  include "NSLog.incl"   local fn PeriodicTable( n as NSInteger ) as CFDictionaryRef NSInteger i, row = 0, start = 0, finish, limits(6,6) CFDictionaryRef dict = NULL   if n < 1 or n > 118 then NSLog( @"Atomic number is out of range." ) : exit fn if n == 1 then dict = @{@"row":@1, @"col":@1}  : exit fn if n == 2 then dict = @{@"row":@1, @"col":@18} : exit fn if n >= 57 and n <= 71 then dict = @{@"row":@8, @"col":fn NumberWithInteger( n - 53 )} : exit fn if n >= 89 and n <= 103 then dict = @{@"row":@9, @"col":fn NumberWithInteger( n - 85 )} : exit fn   limits(0,0) = 3  : limits(0,1) = 10 limits(1,0) = 11 : limits(1,1) = 18 limits(2,0) = 19 : limits(2,1) = 36 limits(3,0) = 37 : limits(3,1) = 54 limits(4,0) = 55 : limits(4,1) = 86 limits(5,0) = 87 : limits(5,1) = 118   for i = 0 to 5 if ( n >= limits(i,0) and n <= limits(i,1) ) row = i + 2 start = limits(i,0) finish = limits(i,1) break end if next   if ( n < start + 2 or row == 4 or row == 5 ) dict = @{@"row":fn NumberWithInteger(row), @"col":fn NumberWithInteger( n - start + 1 )} : exit fn end if dict = @{@"row":fn NumberWithInteger(row), @"col":fn NumberWithInteger( n - finish + 18 )} end fn = dict     local fn BuildTable NSInteger i, count CFArrayRef numbers = @[@1, @2, @29, @42, @57, @58, @59, @71, @72, @89, @90, @103, @113]   count = fn ArrayCount( numbers )   for i = 0 to count -1 CFDictionaryRef coordinates = fn PeriodicTable( fn NumberIntegerValue( numbers[i] ) ) NSLog( @"Atomic number %3d -> (%d, %d)", fn NumberIntegerValue( numbers[i] ), fn NumberIntegerValue( coordinates[@"row"] ), fn NumberIntegerValue( coordinates[@"col"] ) ) next end fn   fn BuildTable   HandleEvents  
http://rosettacode.org/wiki/Periodic_table
Periodic table
Task Display the row and column in the periodic table of the given atomic number. The periodic table Let us consider the following periodic table representation. __________________________________________________________________________ | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | | | |1 H He | | | |2 Li Be B C N O F Ne | | | |3 Na Mg Al Si P S Cl Ar | | | |4 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr | | | |5 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe | | | |6 Cs Ba * Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn | | | |7 Fr Ra ° Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og | |__________________________________________________________________________| | | | | |8 Lantanoidi* La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu | | | |9 Aktinoidi° Ak Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr | |__________________________________________________________________________| Example test cases;   1 -> 1 1   2 -> 1 18   29 -> 4 11   42 -> 5 6   57 -> 8 4   58 -> 8 5   72 -> 6 4   89 -> 9 4 Details; The representation of the periodic table may be represented in various way. The one presented in this challenge does have the following property : Lantanides and Aktinoides are all in a dedicated row, hence there is no element that is placed at 6, 3 nor 7, 3. You may take a look at the atomic number repartitions here. The atomic number is at least 1, at most 118. See also   the periodic table   This task was an idea from CompSciFact   The periodic table in ascii that was used as template
#Go
Go
package main   import ( "fmt" "log" )   var limits = [][2]int{ {3, 10}, {11, 18}, {19, 36}, {37, 54}, {55, 86}, {87, 118}, }   func periodicTable(n int) (int, int) { if n < 1 || n > 118 { log.Fatal("Atomic number is out of range.") } if n == 1 { return 1, 1 } if n == 2 { return 1, 18 } if n >= 57 && n <= 71 { return 8, n - 53 } if n >= 89 && n <= 103 { return 9, n - 85 } var row, start, end int for i := 0; i < len(limits); i++ { limit := limits[i] if n >= limit[0] && n <= limit[1] { row, start, end = i+2, limit[0], limit[1] break } } if n < start+2 || row == 4 || row == 5 { return row, n - start + 1 } return row, n - end + 18 }   func main() { for _, n := range []int{1, 2, 29, 42, 57, 58, 59, 71, 72, 89, 90, 103, 113} { row, col := periodicTable(n) fmt.Printf("Atomic number %3d -> %d, %-2d\n", n, row, col) } }
http://rosettacode.org/wiki/Pig_the_dice_game
Pig the dice game
The   game of Pig   is a multiplayer game played with a single six-sided die.   The object of the game is to reach   100   points or more.   Play is taken in turns.   On each person's turn that person has the option of either: Rolling the dice:   where a roll of two to six is added to their score for that turn and the player's turn continues as the player is given the same choice again;   or a roll of   1   loses the player's total points   for that turn   and their turn finishes with play passing to the next player. Holding:   the player's score for that round is added to their total and becomes safe from the effects of throwing a   1   (one).   The player's turn finishes with play passing to the next player. Task Create a program to score for, and simulate dice throws for, a two-person game. Related task   Pig the dice game/Player
#IS-BASIC
IS-BASIC
100 PROGRAM "Pig.bas" 110 RANDOMIZE 120 STRING PLAYER$(1 TO 2)*28 130 NUMERIC POINTS(1 TO 2),VICTORY(1 TO 2) 140 LET WINNINGSCORE=100 150 TEXT 40:PRINT "Let's play Pig!";CHR$(241):PRINT 160 FOR I=1 TO 2 170 PRINT "Player";I 180 INPUT PROMPT "Whats your name? ":PLAYER$(I) 190 LET POINTS(I)=0:LET VICTORY(I)=0:PRINT 200 NEXT 210 DO 220 CALL TAKETURN(1) 230 IF NOT VICTORY(1) THEN CALL TAKETURN(2) 240 LOOP UNTIL VICTORY(1) OR VICTORY(2) 250 IF VICTORY(1) THEN 260 CALL CONGRAT(1) 270 ELSE 280 CALL CONGRAT(2) 290 END IF 300 DEF TAKETURN(P) 310 LET NEWPOINTS=0 320 SET #102:INK 3:PRINT :PRINT "It's your turn, " PLAYER$(P);"!":PRINT "So far, you have";POINTS(P);"points in all." 330 SET #102:INK 1:PRINT "Do you want to roll the die? (y/n)" 340 LET KEY$=ANSWER$ 350 DO WHILE KEY$="y" 360 LET ROLL=RND(6)+1 370 IF ROLL=1 THEN 380 LET NEWPOINTS=0:LET KEY$="n" 390 PRINT "Oh no! You rolled a 1! No new points after all." 400 ELSE 410 LET NEWPOINTS=NEWPOINTS+ROLL 420 PRINT "You rolled a";ROLL:PRINT "That makes";NEWPOINTS;"new points so far." 430 PRINT "Roll again? (y/n)" 440 LET KEY$=ANSWER$ 450 END IF 460 LOOP 470 IF NEWPOINTS=0 THEN 480 PRINT PLAYER$(P);" still has";POINTS(P);"points." 490 ELSE 500 LET POINTS(P)=POINTS(P)+NEWPOINTS:LET VICTORY(P)=POINTS(P)>=WINNINGSCORE 510 END IF 520 END DEF 530 DEF CONGRAT(P) 540 SET #102:INK 3:PRINT :PRINT "Congratulations ";PLAYER$(P);"!" 550 PRINT "You won with";POINTS(P);"points.":SET #102:INK 1 560 END DEF 570 DEF ANSWER$ 580 LET K$="" 590 DO 600 LET K$=LCASE$(INKEY$) 610 LOOP UNTIL K$="y" OR K$="n" 620 LET ANSWER$=K$ 630 END DEF
http://rosettacode.org/wiki/Pernicious_numbers
Pernicious numbers
A   pernicious number   is a positive integer whose   population count   is a prime. The   population count   is the number of   ones   in the binary representation of a non-negative integer. Example 22   (which is   10110   in binary)   has a population count of   3,   which is prime,   and therefore 22   is a pernicious number. Task display the first   25   pernicious numbers   (in decimal). display all pernicious numbers between   888,888,877   and   888,888,888   (inclusive). display each list of integers on one line   (which may or may not include a title). See also Sequence   A052294 pernicious numbers on The On-Line Encyclopedia of Integer Sequences. Rosetta Code entry   population count, evil numbers, odious numbers.
#CLU
CLU
% The population count of an integer is never going to be % higher than the amount of bits in it (max 64) % so we can get away with a very simple primality test. is_prime = proc (n: int) returns (bool) if n<=2 then return(n=2) end if n//2=0 then return(false) end for i: int in int$from_to_by(n+2, n/2, 2) do if n//i=0 then return(false) end end return(true) end is_prime   % Find the population count of a number pop_count = proc (n: int) returns (int) c: int := 0 while n > 0 do c := c + n // 2 n := n / 2 end return(c) end pop_count   % Is N pernicious? pernicious = proc (n: int) returns (bool) return(is_prime(pop_count(n))) end pernicious   start_up = proc () po: stream := stream$primary_output()   stream$putl(po, "First 25 pernicious numbers: ") n: int := 1 seen: int := 0 while seen<25 do if pernicious(n) then stream$puts(po, int$unparse(n) || " ") seen := seen + 1 end n := n + 1 end   stream$putl(po, "\nPernicious numbers between 888,888,877 and 888,888,888:") for i: int in int$from_to(888888877,888888888) do if pernicious(i) then stream$puts(po, int$unparse(i) || " ") end end end start_up
http://rosettacode.org/wiki/Pernicious_numbers
Pernicious numbers
A   pernicious number   is a positive integer whose   population count   is a prime. The   population count   is the number of   ones   in the binary representation of a non-negative integer. Example 22   (which is   10110   in binary)   has a population count of   3,   which is prime,   and therefore 22   is a pernicious number. Task display the first   25   pernicious numbers   (in decimal). display all pernicious numbers between   888,888,877   and   888,888,888   (inclusive). display each list of integers on one line   (which may or may not include a title). See also Sequence   A052294 pernicious numbers on The On-Line Encyclopedia of Integer Sequences. Rosetta Code entry   population count, evil numbers, odious numbers.
#COBOL
COBOL
IDENTIFICATION DIVISION. PROGRAM-ID. PERNICIOUS-NUMBERS.   DATA DIVISION. WORKING-STORAGE SECTION. 01 VARIABLES. 03 AMOUNT PIC 99. 03 CAND PIC 9(9). 03 POPCOUNT PIC 99. 03 POP-N PIC 9(9). 03 FILLER REDEFINES POP-N. 05 FILLER PIC 9(8). 05 FILLER PIC 9. 88 ODD VALUES 1, 3, 5, 7, 9. 03 DSOR PIC 99. 03 DIV-RSLT PIC 99V99. 03 FILLER REDEFINES DIV-RSLT. 05 FILLER PIC 99. 05 FILLER PIC 99. 88 DIVISIBLE VALUE ZERO. 03 PRIME-FLAG PIC X. 88 PRIME VALUE '*'.   01 FORMAT. 03 SIZE-FLAG PIC X. 88 SMALL VALUE 'S'. 88 LARGE VALUE 'L'. 03 SMALL-NUM PIC ZZ9. 03 LARGE-NUM PIC Z(9)9. 03 OUT-STR PIC X(80). 03 OUT-PTR PIC 99.   PROCEDURE DIVISION. BEGIN. PERFORM SMALL-PERNICIOUS. PERFORM LARGE-PERNICIOUS. STOP RUN.   INIT-OUTPUT-VARS. MOVE ZERO TO AMOUNT. MOVE 1 TO OUT-PTR. MOVE SPACES TO OUT-STR.   SMALL-PERNICIOUS. PERFORM INIT-OUTPUT-VARS. MOVE 'S' TO SIZE-FLAG. PERFORM ADD-PERNICIOUS VARYING CAND FROM 1 BY 1 UNTIL AMOUNT IS EQUAL TO 25. DISPLAY OUT-STR.   LARGE-PERNICIOUS. PERFORM INIT-OUTPUT-VARS. MOVE 'L' TO SIZE-FLAG. PERFORM ADD-PERNICIOUS VARYING CAND FROM 888888877 BY 1 UNTIL CAND IS GREATER THAN 888888888. DISPLAY OUT-STR.   ADD-NUM. ADD 1 TO AMOUNT. IF SMALL, MOVE CAND TO SMALL-NUM, STRING SMALL-NUM DELIMITED BY SIZE INTO OUT-STR WITH POINTER OUT-PTR. IF LARGE, MOVE CAND TO LARGE-NUM, STRING LARGE-NUM DELIMITED BY SIZE INTO OUT-STR WITH POINTER OUT-PTR.   ADD-PERNICIOUS. PERFORM FIND-POPCOUNT. PERFORM CHECK-PRIME. IF PRIME, PERFORM ADD-NUM.   FIND-POPCOUNT. MOVE ZERO TO POPCOUNT. MOVE CAND TO POP-N. PERFORM COUNT-BIT UNTIL POP-N IS EQUAL TO ZERO.   COUNT-BIT. IF ODD, ADD 1 TO POPCOUNT. DIVIDE 2 INTO POP-N.   CHECK-PRIME. IF POPCOUNT IS LESS THAN 2, MOVE SPACE TO PRIME-FLAG ELSE MOVE '*' TO PRIME-FLAG. PERFORM CHECK-DSOR VARYING DSOR FROM 2 BY 1 UNTIL NOT PRIME OR DSOR IS NOT LESS THAN POPCOUNT.   CHECK-DSOR. DIVIDE POPCOUNT BY DSOR GIVING DIV-RSLT. IF DIVISIBLE, MOVE SPACE TO PRIME-FLAG.
http://rosettacode.org/wiki/Permutations/Rank_of_a_permutation
Permutations/Rank of a permutation
A particular ranking of a permutation associates an integer with a particular ordering of all the permutations of a set of distinct items. For our purposes the ranking will assign integers 0.. ( n ! − 1 ) {\displaystyle 0..(n!-1)} to an ordering of all the permutations of the integers 0.. ( n − 1 ) {\displaystyle 0..(n-1)} . For example, the permutations of the digits zero to 3 arranged lexicographically have the following rank: PERMUTATION RANK (0, 1, 2, 3) -> 0 (0, 1, 3, 2) -> 1 (0, 2, 1, 3) -> 2 (0, 2, 3, 1) -> 3 (0, 3, 1, 2) -> 4 (0, 3, 2, 1) -> 5 (1, 0, 2, 3) -> 6 (1, 0, 3, 2) -> 7 (1, 2, 0, 3) -> 8 (1, 2, 3, 0) -> 9 (1, 3, 0, 2) -> 10 (1, 3, 2, 0) -> 11 (2, 0, 1, 3) -> 12 (2, 0, 3, 1) -> 13 (2, 1, 0, 3) -> 14 (2, 1, 3, 0) -> 15 (2, 3, 0, 1) -> 16 (2, 3, 1, 0) -> 17 (3, 0, 1, 2) -> 18 (3, 0, 2, 1) -> 19 (3, 1, 0, 2) -> 20 (3, 1, 2, 0) -> 21 (3, 2, 0, 1) -> 22 (3, 2, 1, 0) -> 23 Algorithms exist that can generate a rank from a permutation for some particular ordering of permutations, and that can generate the same rank from the given individual permutation (i.e. given a rank of 17 produce (2, 3, 1, 0) in the example above). One use of such algorithms could be in generating a small, random, sample of permutations of n {\displaystyle n} items without duplicates when the total number of permutations is large. Remember that the total number of permutations of n {\displaystyle n} items is given by n ! {\displaystyle n!} which grows large very quickly: A 32 bit integer can only hold 12 ! {\displaystyle 12!} , a 64 bit integer only 20 ! {\displaystyle 20!} . It becomes difficult to take the straight-forward approach of generating all permutations then taking a random sample of them. A question on the Stack Overflow site asked how to generate one million random and indivudual permutations of 144 items. Task Create a function to generate a permutation from a rank. Create the inverse function that given the permutation generates its rank. Show that for n = 3 {\displaystyle n=3} the two functions are indeed inverses of each other. Compute and show here 4 random, individual, samples of permutations of 12 objects. Stretch goal State how reasonable it would be to use your program to address the limits of the Stack Overflow question. References Ranking and Unranking Permutations in Linear Time by Myrvold & Ruskey. (Also available via Google here). Ranks on the DevData site. Another answer on Stack Overflow to a different question that explains its algorithm in detail. Related tasks Factorial_base_numbers_indexing_permutations_of_a_collection
#Racket
Racket
  #lang racket (require math) (define-syntax def (make-rename-transformer #'match-define-values))   (define (perm xs n) (cond [(empty? xs) '()] [else (def (q r) (quotient/remainder n (factorial (sub1 (length xs))))) (def (a (cons c b)) (split-at xs q)) (cons c (perm (append a b) r))]))   (define (rank ys) (cond [(empty? ys) 0] [else (def ((cons x0 xs)) ys) (+ (rank xs) (* (for/sum ([x xs] #:when (< x x0)) 1) (factorial (length xs))))]))  
http://rosettacode.org/wiki/Permutations/Rank_of_a_permutation
Permutations/Rank of a permutation
A particular ranking of a permutation associates an integer with a particular ordering of all the permutations of a set of distinct items. For our purposes the ranking will assign integers 0.. ( n ! − 1 ) {\displaystyle 0..(n!-1)} to an ordering of all the permutations of the integers 0.. ( n − 1 ) {\displaystyle 0..(n-1)} . For example, the permutations of the digits zero to 3 arranged lexicographically have the following rank: PERMUTATION RANK (0, 1, 2, 3) -> 0 (0, 1, 3, 2) -> 1 (0, 2, 1, 3) -> 2 (0, 2, 3, 1) -> 3 (0, 3, 1, 2) -> 4 (0, 3, 2, 1) -> 5 (1, 0, 2, 3) -> 6 (1, 0, 3, 2) -> 7 (1, 2, 0, 3) -> 8 (1, 2, 3, 0) -> 9 (1, 3, 0, 2) -> 10 (1, 3, 2, 0) -> 11 (2, 0, 1, 3) -> 12 (2, 0, 3, 1) -> 13 (2, 1, 0, 3) -> 14 (2, 1, 3, 0) -> 15 (2, 3, 0, 1) -> 16 (2, 3, 1, 0) -> 17 (3, 0, 1, 2) -> 18 (3, 0, 2, 1) -> 19 (3, 1, 0, 2) -> 20 (3, 1, 2, 0) -> 21 (3, 2, 0, 1) -> 22 (3, 2, 1, 0) -> 23 Algorithms exist that can generate a rank from a permutation for some particular ordering of permutations, and that can generate the same rank from the given individual permutation (i.e. given a rank of 17 produce (2, 3, 1, 0) in the example above). One use of such algorithms could be in generating a small, random, sample of permutations of n {\displaystyle n} items without duplicates when the total number of permutations is large. Remember that the total number of permutations of n {\displaystyle n} items is given by n ! {\displaystyle n!} which grows large very quickly: A 32 bit integer can only hold 12 ! {\displaystyle 12!} , a 64 bit integer only 20 ! {\displaystyle 20!} . It becomes difficult to take the straight-forward approach of generating all permutations then taking a random sample of them. A question on the Stack Overflow site asked how to generate one million random and indivudual permutations of 144 items. Task Create a function to generate a permutation from a rank. Create the inverse function that given the permutation generates its rank. Show that for n = 3 {\displaystyle n=3} the two functions are indeed inverses of each other. Compute and show here 4 random, individual, samples of permutations of 12 objects. Stretch goal State how reasonable it would be to use your program to address the limits of the Stack Overflow question. References Ranking and Unranking Permutations in Linear Time by Myrvold & Ruskey. (Also available via Google here). Ranks on the DevData site. Another answer on Stack Overflow to a different question that explains its algorithm in detail. Related tasks Factorial_base_numbers_indexing_permutations_of_a_collection
#Raku
Raku
use v6;   sub rank2inv ( $rank, $n = * ) { $rank.polymod( 1 ..^ $n ); }   sub inv2rank ( @inv ) { [+] @inv Z* [\*] 1, 1, * + 1 ... * }   sub inv2perm ( @inv, @items is copy = ^@inv.elems ) { my @perm; for @inv.reverse -> $i { @perm.append: @items.splice: $i, 1; } @perm; }   sub perm2inv ( @perm ) { #not in linear time ( { @perm[++$ .. *].grep( * < $^cur ).elems } for @perm; ).reverse; }   for ^6 { my @row.push: $^rank; for ( *.&rank2inv(3) , &inv2perm, &perm2inv, &inv2rank ) -> &code { @row.push: code( @row[*-1] ); } say @row; }   my $perms = 4; #100; my $n = 12; #144;   say 'Via BigInt rank'; for ( ( ^([*] 1 .. $n) ).pick($perms) ) { say $^rank.&rank2inv($n).&inv2perm; };   say 'Via inversion vectors'; for ( { my $i=0; inv2perm (^++$i).roll xx $n } ... * ).unique( with => &[eqv] ).[^$perms] { .say; };   say 'Via Raku method pick'; for ( { [(^$n).pick(*)] } ... * ).unique( with => &[eqv] ).head($perms) { .say };  
http://rosettacode.org/wiki/Pierpont_primes
Pierpont primes
A Pierpont prime is a prime number of the form: 2u3v + 1 for some non-negative integers u and v . A Pierpont prime of the second kind is a prime number of the form: 2u3v - 1 for some non-negative integers u and v . The term "Pierpont primes" is generally understood to mean the first definition, but will be called "Pierpont primes of the first kind" on this page to distinguish them. Task Write a routine (function, procedure, whatever) to find Pierpont primes of the first & second kinds. Use the routine to find and display here, on this page, the first 50 Pierpont primes of the first kind. Use the routine to find and display here, on this page, the first 50 Pierpont primes of the second kind If your language supports large integers, find and display here, on this page, the 250th Pierpont prime of the first kind and the 250th Pierpont prime of the second kind. See also Wikipedia - Pierpont primes OEIS:A005109 - Class 1 -, or Pierpont primes OEIS:A005105 - Class 1 +, or Pierpont primes of the second kind
#Nim
Nim
import math, strutils   func isPrime(n: int): bool = ## Check if "n" is prime by trying successive divisions. ## "n" is supposed not to be a multiple of 2 or 3. var d = 5 var delta = 2 while d <= int(sqrt(n.toFloat)): if n mod d == 0: return false inc d, delta delta = 6 - delta result = true   func isProduct23(n: int): bool = ## Check if "n" has only 2 and 3 for prime divisors ## (i.e. that "n = 2^u * 3^v"). var n = n while (n and 1) == 0: n = n shr 1 while n mod 3 == 0: n = n div 3 result = n == 1   iterator pierpont(maxCount: Positive; k: int): int = ## Yield the Pierpoint primes of first or second kind according ## to the value of "k" (+1 for first kind, -1 for second kind). yield 2 yield 3 var n = 5 var delta = 2 # 2 and 4 alternatively to skip the multiples of 2 and 3. yield n var count = 3 while count < maxCount: inc n, delta delta = 6 - delta if isProduct23(n - k) and isPrime(n): inc count yield n   template pierpont1*(maxCount: Positive): int = pierpont(maxCount, +1) template pierpont2*(maxCount: Positive): int = pierpont(maxCount, -1)     when isMainModule:   echo "First 50 Pierpont primes of the first kind:" var count = 0 for n in pierpont1(50): stdout.write ($n).align(9) inc count if count mod 10 == 0: stdout.write '\n'   echo "" echo "First 50 Pierpont primes of the second kind:" count = 0 for n in pierpont2(50): stdout.write ($n).align(9) inc count if count mod 10 == 0: stdout.write '\n'
http://rosettacode.org/wiki/Pick_random_element
Pick random element
Demonstrate how to pick a random element from a list.
#Euphoria
Euphoria
constant s = {'a', 'b', 'c'} puts(1,s[rand($)])
http://rosettacode.org/wiki/Pick_random_element
Pick random element
Demonstrate how to pick a random element from a list.
#F.23
F#
let list = ["a"; "b"; "c"; "d"; "e"] let rand = new System.Random() printfn "%s" list.[rand.Next(list.Length)]
http://rosettacode.org/wiki/Primality_by_trial_division
Primality by trial division
Task Write a boolean function that tells whether a given integer is prime. Remember that   1   and all non-positive numbers are not prime. Use trial division. Even numbers greater than   2   may be eliminated right away. A loop from   3   to   √ n    will suffice,   but other loops are allowed. Related tasks   count in factors   prime decomposition   AKS test for primes   factors of an integer   Sieve of Eratosthenes   factors of a Mersenne number   trial factoring of a Mersenne number   partition an integer X into N primes   sequence of primes by Trial Division
#UNIX_Shell
UNIX Shell
function primep { typeset n=$1 p=3 (( n == 2 )) && return 0 # 2 is prime. (( n & 1 )) || return 1 # Other evens are not prime. (( n >= 3 )) || return 1   # Loop for odd p from 3 to sqrt(n). # Comparing p * p <= n can overflow. while (( p <= n / p )); do # If p divides n, then n is not prime. (( n % p )) || return 1 (( p += 2 )) done return 0 # Yes, n is prime. }
http://rosettacode.org/wiki/Phrase_reversals
Phrase reversals
Task Given a string of space separated words containing the following phrase: rosetta code phrase reversal Reverse the characters of the string. Reverse the characters of each individual word in the string, maintaining original word order within the string. Reverse the order of each word of the string, maintaining the order of characters in each word. Show your output here. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#Emacs_Lisp
Emacs Lisp
(defun reverse-sep (words sep) (mapconcat 'identity (reverse (split-string words sep)) sep))   (defun reverse-chars (line) (reverse-sep line ""))   (defun reverse-words (line) (reverse-sep line " "))   (defvar line "rosetta code phrase reversal")   (with-output-to-temp-buffer "*reversals*" (princ (reverse-chars line)) (terpri) (princ (mapconcat 'identity (mapcar #'reverse-chars (split-string line)) " ")) (terpri) (princ (reverse-words line)) (terpri))
http://rosettacode.org/wiki/Permutations/Derangements
Permutations/Derangements
A derangement is a permutation of the order of distinct items in which no item appears in its original place. For example, the only two derangements of the three items (0, 1, 2) are (1, 2, 0), and (2, 0, 1). The number of derangements of n distinct items is known as the subfactorial of n, sometimes written as !n. There are various ways to calculate !n. Task Create a named function/method/subroutine/... to generate derangements of the integers 0..n-1, (or 1..n if you prefer). Generate and show all the derangements of 4 integers using the above routine. Create a function that calculates the subfactorial of n, !n. Print and show a table of the counted number of derangements of n vs. the calculated !n for n from 0..9 inclusive. Optional stretch goal   Calculate    !20 Related tasks   Anagrams/Deranged anagrams   Best shuffle   Left_factorials Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#C.23
C#
  using System; class Derangements { static int n = 4; static int [] buf = new int [n]; static bool [] used = new bool [n];   static void Main() { for (int i = 0; i < n; i++) used [i] = false; rec(0); }   static void rec(int ind) { for (int i = 0; i < n; i++) { if (!used [i] && i != ind) { used [i] = true; buf [ind] = i; if (ind + 1 < n) rec(ind + 1); else Console.WriteLine(string.Join(",", buf)); used [i] = false; } } } }  
http://rosettacode.org/wiki/Permutations_by_swapping
Permutations by swapping
Task Generate permutations of n items in which successive permutations differ from each other by the swapping of any two items. Also generate the sign of the permutation which is +1 when the permutation is generated from an even number of swaps from the initial state, and -1 for odd. Show the permutations and signs of three items, in order of generation here. Such data are of use in generating the determinant of a square matrix and any functions created should bear this in mind. Note: The Steinhaus–Johnson–Trotter algorithm generates successive permutations where adjacent items are swapped, but from this discussion adjacency is not a requirement. References Steinhaus–Johnson–Trotter algorithm Johnson-Trotter Algorithm Listing All Permutations Heap's algorithm [1] Tintinnalogia Related tasks   Matrix arithmetic   Gray code
#Common_Lisp
Common Lisp
(defstruct (directed-number (:conc-name dn-)) (number nil :type integer) (direction nil :type (member :left :right)))   (defmethod print-object ((dn directed-number) stream) (ecase (dn-direction dn) (:left (format stream "<~D" (dn-number dn))) (:right (format stream "~D>" (dn-number dn)))))   (defun dn> (dn1 dn2) (declare (directed-number dn1 dn2)) (> (dn-number dn1) (dn-number dn2)))   (defun dn-reverse-direction (dn) (declare (directed-number dn)) (setf (dn-direction dn) (ecase (dn-direction dn) (:left :right) (:right :left))))   (defun make-directed-numbers-upto (upto) (let ((numbers (make-array upto :element-type 'integer))) (dotimes (n upto numbers) (setf (aref numbers n) (make-directed-number :number (1+ n) :direction :left)))))   (defun max-mobile-pos (numbers) (declare ((vector directed-number) numbers)) (loop with pos-limit = (1- (length numbers)) with max-value and max-pos for num across numbers for pos from 0 do (ecase (dn-direction num) (:left (when (and (plusp pos) (dn> num (aref numbers (1- pos))) (or (null max-value) (dn> num max-value))) (setf max-value num max-pos pos))) (:right (when (and (< pos pos-limit) (dn> num (aref numbers (1+ pos))) (or (null max-value) (dn> num max-value))) (setf max-value num max-pos pos)))) finally (return max-pos)))   (defun permutations (upto) (loop with numbers = (make-directed-numbers-upto upto) for max-mobile-pos = (max-mobile-pos numbers) for sign = 1 then (- sign) do (format t "~A sign: ~:[~;+~]~D~%" numbers (plusp sign) sign) while max-mobile-pos do (let ((max-mobile-number (aref numbers max-mobile-pos))) (ecase (dn-direction max-mobile-number) (:left (rotatef (aref numbers (1- max-mobile-pos)) (aref numbers max-mobile-pos))) (:right (rotatef (aref numbers max-mobile-pos) (aref numbers (1+ max-mobile-pos))))) (loop for n across numbers when (dn> n max-mobile-number) do (dn-reverse-direction n)))))   (permutations 3) (permutations 4)
http://rosettacode.org/wiki/Permutation_test
Permutation test
Permutation test You are encouraged to solve this task according to the task description, using any language you may know. A new medical treatment was tested on a population of n + m {\displaystyle n+m} volunteers, with each volunteer randomly assigned either to a group of n {\displaystyle n} treatment subjects, or to a group of m {\displaystyle m} control subjects. Members of the treatment group were given the treatment, and members of the control group were given a placebo. The effect of the treatment or placebo on each volunteer was measured and reported in this table. Table of experimental results Treatment group Control group 85 68 88 41 75 10 66 49 25 16 29 65 83 32 39 92 97 28 98 Write a program that performs a permutation test to judge whether the treatment had a significantly stronger effect than the placebo. Do this by considering every possible alternative assignment from the same pool of volunteers to a treatment group of size n {\displaystyle n} and a control group of size m {\displaystyle m} (i.e., the same group sizes used in the actual experiment but with the group members chosen differently), while assuming that each volunteer's effect remains constant regardless. Note that the number of alternatives will be the binomial coefficient ( n + m n ) {\displaystyle {\tbinom {n+m}{n}}} . Compute the mean effect for each group and the difference in means between the groups in every case by subtracting the mean of the control group from the mean of the treatment group. Report the percentage of alternative groupings for which the difference in means is less or equal to the actual experimentally observed difference in means, and the percentage for which it is greater. Note that they should sum to 100%. Extremely dissimilar values are evidence of an effect not entirely due to chance, but your program need not draw any conclusions. You may assume the experimental data are known at compile time if that's easier than loading them at run time. Test your solution on the data given above.
#Elixir
Elixir
defmodule Permutation do def statistic(ab, a) do sumab = Enum.sum(ab) suma = Enum.sum(a) suma / length(a) - (sumab - suma) / (length(ab) - length(a)) end   def test(a, b) do ab = a ++ b tobs = statistic(ab, a) {under, count} = Enum.reduce(comb(ab, length(a)), {0,0}, fn perm, {under, count} -> if statistic(ab, perm) <= tobs, do: {under+1, count+1}, else: {under , count+1} end) under * 100.0 / count end   defp comb(_, 0), do: [[]] defp comb([], _), do: [] defp comb([h|t], m) do (for l <- comb(t, m-1), do: [h|l]) ++ comb(t, m) end end   treatmentGroup = [85, 88, 75, 66, 25, 29, 83, 39, 97] controlGroup = [68, 41, 10, 49, 16, 65, 32, 92, 28, 98] under = Permutation.test(treatmentGroup, controlGroup) :io.fwrite "under = ~.2f%, over = ~.2f%~n", [under, 100-under]
http://rosettacode.org/wiki/Permutation_test
Permutation test
Permutation test You are encouraged to solve this task according to the task description, using any language you may know. A new medical treatment was tested on a population of n + m {\displaystyle n+m} volunteers, with each volunteer randomly assigned either to a group of n {\displaystyle n} treatment subjects, or to a group of m {\displaystyle m} control subjects. Members of the treatment group were given the treatment, and members of the control group were given a placebo. The effect of the treatment or placebo on each volunteer was measured and reported in this table. Table of experimental results Treatment group Control group 85 68 88 41 75 10 66 49 25 16 29 65 83 32 39 92 97 28 98 Write a program that performs a permutation test to judge whether the treatment had a significantly stronger effect than the placebo. Do this by considering every possible alternative assignment from the same pool of volunteers to a treatment group of size n {\displaystyle n} and a control group of size m {\displaystyle m} (i.e., the same group sizes used in the actual experiment but with the group members chosen differently), while assuming that each volunteer's effect remains constant regardless. Note that the number of alternatives will be the binomial coefficient ( n + m n ) {\displaystyle {\tbinom {n+m}{n}}} . Compute the mean effect for each group and the difference in means between the groups in every case by subtracting the mean of the control group from the mean of the treatment group. Report the percentage of alternative groupings for which the difference in means is less or equal to the actual experimentally observed difference in means, and the percentage for which it is greater. Note that they should sum to 100%. Extremely dissimilar values are evidence of an effect not entirely due to chance, but your program need not draw any conclusions. You may assume the experimental data are known at compile time if that's easier than loading them at run time. Test your solution on the data given above.
#GAP
GAP
a := [85, 88, 75, 66, 25, 29, 83, 39, 97]; b := [68, 41, 10, 49, 16, 65, 32, 92, 28, 98];   # Compute a decimal approximation of a rational Approx := function(x, d) local neg, a, b, n, m, s; if x < 0 then x := -x; neg := true; else neg := false; fi; a := NumeratorRat(x); b := DenominatorRat(x); n := QuoInt(a, b); a := RemInt(a, b); m := 10^d; s := ""; if neg then Append(s, "-"); fi; Append(s, String(n)); n := Size(s) + 1; Append(s, String(m + QuoInt(a*m, b))); s[n] := '.'; return s; end;   PermTest := function(a, b) local c, d, p, q, u, v, m, n, k, diff, all; p := Size(a); q := Size(b); v := Concatenation(a, b); n := p + q; m := Binomial(n, p); diff := Sum(a)/p - Sum(b)/q; all := [1 .. n]; k := 0; for u in Combinations(all, p) do c := List(u, i -> v[i]); d := List(Difference(all, u), i -> v[i]); if Sum(c)/p - Sum(d)/q > diff then k := k + 1; fi; od; return [Approx((1 - k/m)*100, 3), Approx(k/m*100, 3)]; end;   # in order, % less or greater than original diff PermTest(a, b); [ "87.197", "12.802" ]
http://rosettacode.org/wiki/Percolation/Mean_run_density
Percolation/Mean run density
Percolation Simulation This is a simulation of aspects of mathematical percolation theory. For other percolation simulations, see Category:Percolation Simulations, or: 1D finite grid simulation Mean run density 2D finite grid simulations Site percolation | Bond percolation | Mean cluster density Let v {\displaystyle v} be a vector of n {\displaystyle n} values of either 1 or 0 where the probability of any value being 1 is p {\displaystyle p} ; the probability of a value being 0 is therefore 1 − p {\displaystyle 1-p} . Define a run of 1s as being a group of consecutive 1s in the vector bounded either by the limits of the vector or by a 0. Let the number of such runs in a given vector of length n {\displaystyle n} be R n {\displaystyle R_{n}} . For example, the following vector has R 10 = 3 {\displaystyle R_{10}=3} [1 1 0 0 0 1 0 1 1 1] ^^^ ^ ^^^^^ Percolation theory states that K ( p ) = lim n → ∞ R n / n = p ( 1 − p ) {\displaystyle K(p)=\lim _{n\to \infty }R_{n}/n=p(1-p)} Task Any calculation of R n / n {\displaystyle R_{n}/n} for finite n {\displaystyle n} is subject to randomness so should be computed as the average of t {\displaystyle t} runs, where t ≥ 100 {\displaystyle t\geq 100} . For values of p {\displaystyle p} of 0.1, 0.3, 0.5, 0.7, and 0.9, show the effect of varying n {\displaystyle n} on the accuracy of simulated K ( p ) {\displaystyle K(p)} . Show your output here. See also s-Run on Wolfram mathworld.
#11l
11l
UInt32 seed = 0 F nonrandom()  :seed = 1664525 * :seed + 1013904223 R Int(:seed >> 16) / Float(FF'FF)   V (p, t) = (0.5, 500)   F newv(n, p) R (0 .< n).map(i -> Int(nonrandom() < @p))   F runs(v) R sum(zip(v, v[1..] [+] [0]).map((a, b) -> (a [&] (-)b)))   F mean_run_density(n, p) R runs(newv(n, p)) / Float(n)   L(p10) (1.<10).step(2) p = p10 / 10 V limit = p * (1 - p) print(‘’) L(n2) (10.<16).step(2) V n = 2 ^ n2 V sim = sum((0 .< t).map(i -> mean_run_density(@n, :p))) / t print(‘t=#3 p=#.2 n=#5 p(1-p)=#.3 sim=#.3 delta=#.1%’.format( t, p, n, limit, sim, I limit {abs(sim - limit) / limit * 100} E sim * 100))
http://rosettacode.org/wiki/Percolation/Site_percolation
Percolation/Site percolation
Percolation Simulation This is a simulation of aspects of mathematical percolation theory. For other percolation simulations, see Category:Percolation Simulations, or: 1D finite grid simulation Mean run density 2D finite grid simulations Site percolation | Bond percolation | Mean cluster density Given an M × N {\displaystyle M\times N} rectangular array of cells numbered c e l l [ 0.. M − 1 , 0.. N − 1 ] {\displaystyle \mathrm {cell} [0..M-1,0..N-1]} assume M {\displaystyle M} is horizontal and N {\displaystyle N} is downwards. Assume that the probability of any cell being filled is a constant p {\displaystyle p} where 0.0 ≤ p ≤ 1.0 {\displaystyle 0.0\leq p\leq 1.0} The task Simulate creating the array of cells with probability p {\displaystyle p} and then testing if there is a route through adjacent filled cells from any on row 0 {\displaystyle 0} to any on row N {\displaystyle N} , i.e. testing for site percolation. Given p {\displaystyle p} repeat the percolation t {\displaystyle t} times to estimate the proportion of times that the fluid can percolate to the bottom for any given p {\displaystyle p} . Show how the probability of percolating through the random grid changes with p {\displaystyle p} going from 0.0 {\displaystyle 0.0} to 1.0 {\displaystyle 1.0} in 0.1 {\displaystyle 0.1} increments and with the number of repetitions to estimate the fraction at any given p {\displaystyle p} as t >= 100 {\displaystyle t>=100} . Use an M = 15 , N = 15 {\displaystyle M=15,N=15} grid of cells for all cases. Optionally depict a percolation through a cell grid graphically. Show all output on this page.
#11l
11l
UInt32 seed = 0 F nonrandom()  :seed = 1664525 * :seed + 1013904223 R Int(:seed >> 16) / Float(FF'FF)   V (M, nn, t) = (15, 15, 100)   V cell2char = ‘ #abcdefghijklmnopqrstuvwxyz’ V NOT_VISITED = 1   T PercolatedException (Int, Int) t   F (t) .t = t   F newgrid(p) R (0 .< :nn).map(n -> (0 .< :M).map(m -> Int(nonrandom() < @@p)))   F pgrid(cell, percolated) L(n) 0 .< :nn print(‘#.) ’.format(n % 10)‘’(0 .< :M).map(m -> :cell2char[@cell[@n][m]]).join(‘ ’)) I percolated != (-1, -1) V where = percolated[0] print(‘!) ’(‘ ’ * where)‘’:cell2char[cell[:nn - 1][where]])   F walk_maze(m, n, &cell, indx) -> N cell[n][m] = indx I n < :nn - 1 & cell[n + 1][m] == :NOT_VISITED walk_maze(m, n + 1, &cell, indx) E I n == :nn - 1 X PercolatedException((m, indx)) I m & cell[n][m - 1] == :NOT_VISITED walk_maze(m - 1, n, &cell, indx) I m < :M - 1 & cell[n][m + 1] == :NOT_VISITED walk_maze(m + 1, n, &cell, indx) I n & cell[n - 1][m] == :NOT_VISITED walk_maze(m, n - 1, &cell, indx)   F check_from_top(&cell) -> (Int, Int)? V (n, walk_index) = (0, 1) X.try L(m) 0 .< :M I cell[n][m] == :NOT_VISITED walk_index++ walk_maze(m, n, &cell, walk_index) X.catch PercolatedException ex R ex.t R N   V sample_printed = 0B [Float = Int] pcount L(p10) 11 V p = p10 / 10.0 pcount[p] = 0 L(tries) 0 .< t V cell = newgrid(p) (Int, Int)? percolated = check_from_top(&cell) I percolated != N pcount[p]++ I !sample_printed print("\nSample percolating #. x #., p = #2.2 grid\n".format(M, nn, p)) pgrid(cell, percolated) sample_printed = 1B print("\n p: Fraction of #. tries that percolate through\n".format(t))   L(p, c) sorted(pcount.items()) print(‘#.1: #.’.format(p, c / Float(t)))
http://rosettacode.org/wiki/Perlin_noise
Perlin noise
The   Perlin noise   is a kind of   gradient noise   invented by   Ken Perlin   around the end of the twentieth century and still currently heavily used in   computer graphics,   most notably to procedurally generate textures or heightmaps. The Perlin noise is basically a   pseudo-random   mapping of   R d {\displaystyle \mathbb {R} ^{d}}   into   R {\displaystyle \mathbb {R} }   with an integer   d {\displaystyle d}   which can be arbitrarily large but which is usually   2,   3,   or   4. Either by using a dedicated library or by implementing the algorithm, show that the Perlin noise   (as defined in 2002 in the Java implementation below)   of the point in 3D-space with coordinates     3.14,   42,   7     is     0.13691995878400012. Note: this result assumes 64 bit IEEE-754 floating point calculations. If your language uses a different floating point representation, make a note of it and calculate the value accurate to 15 decimal places, or your languages accuracy threshold if it is less. Trailing zeros need not be displayed.
#Common_Lisp
Common Lisp
;;;; Translation from: Java   (declaim (optimize (speed 3) (debug 0)))   (defconstant +p+ (let ((permutation #(151 160 137 91 90 15 131 13 201 95 96 53 194 233 7 225 140 36 103 30 69 142 8 99 37 240 21 10 23 190 6 148 247 120 234 75 0 26 197 62 94 252 219 203 117 35 11 32 57 177 33 88 237 149 56 87 174 20 125 136 171 168 68 175 74 165 71 134 139 48 27 166 77 146 158 231 83 111 229 122 60 211 133 230 220 105 92 41 55 46 245 40 244 102 143 54 65 25 63 161 1 216 80 73 209 76 132 187 208 89 18 169 200 196 135 130 116 188 159 86 164 100 109 198 173 186 3 64 52 217 226 250 124 123 5 202 38 147 118 126 255 82 85 212 207 206 59 227 47 16 58 17 182 189 28 42 223 183 170 213 119 248 152 2 44 154 163 70 221 153 101 155 167 43 172 9 129 22 39 253 19 98 108 110 79 113 224 232 178 185 112 104 218 246 97 228 251 34 242 193 238 210 144 12 191 179 162 241 81 51 145 235 249 14 239 107 49 192 214 31 181 199 106 157 184 84 204 176 115 121 50 45 127 4 150 254 138 236 205 93 222 114 67 29 24 72 243 141 128 195 78 66 215 61 156 180)) (aux (make-array 512 :element-type 'fixnum))) (dotimes (i 256 aux) (setf (aref aux i) (aref permutation i)) (setf (aref aux (+ 256 i)) (aref permutation i)))))   (defun fade (te) (declare (type double-float te)) (the double-float (* te te te (+ (* te (- (* te 6) 15)) 10))))   (defun lerp (te a b) (declare (type double-float te a b)) (the double-float (+ a (* te (- b a)))))   (defun grad (hash x y z) (declare (type fixnum hash) (type double-float x y z)) (let* ((h (logand hash 15)) ;; convert lo 4 bits of hash code into 12 gradient directions (u (if (< h 8) x y)) (v (cond ((< h 4) y) ((or (= h 12) (= h 14)) x) (t z)))) (the double-float (+ (if (zerop (logand h 1)) u (- u)) (if (zerop (logand h 2)) v (- v))))))   (defun noise (x y z) (declare (type double-float x y z)) ;; find unit cube that contains point. (let ((cx (logand (floor x) 255)) (cy (logand (floor y) 255)) (cz (logand (floor z) 255))) ;; find relative x, y, z of point in cube. (let ((x (- x (floor x))) (y (- y (floor y))) (z (- z (floor z)))) ;; compute fade curves for each of x, y, z. (let ((u (fade x)) (v (fade y)) (w (fade z))) ;; hash coordinates of the 8 cube corners, (let* ((ca (+ (aref +p+ cx) cy)) (caa (+ (aref +p+ ca) cz)) (cab (+ (aref +p+ (1+ ca)) cz)) (cb (+ (aref +p+ (1+ cx)) cy)) (cba (+ (aref +p+ cb) cz)) (cbb (+ (aref +p+ (1+ cb)) cz))) ;; ... and add blended results from 8 corners of cube (the double-float (lerp w (lerp v (lerp u (grad (aref +p+ caa) x y z) (grad (aref +p+ cba) (1- x) y z)) (lerp u (grad (aref +p+ cab) x (1- y) z) (grad (aref +p+ cbb) (1- x) (1- y) z))) (lerp v (lerp u (grad (aref +p+ (1+ caa)) x y (1- z)) (grad (aref +p+ (1+ cba)) (1- x) y (1- z))) (lerp u (grad (aref +p+ (1+ cab)) x (1- y) (1- z)) (grad (aref +p+ (1+ cbb)) (1- x) (1- y) (1- z)))))))))))   (print (noise 3.14d0 42d0 7d0))  
http://rosettacode.org/wiki/Perfect_totient_numbers
Perfect totient numbers
Generate and show here, the first twenty Perfect totient numbers. Related task   Totient function Also see   the OEIS entry for   perfect totient numbers.   mrob   list of the first 54
#Arturo
Arturo
totient: function [n][ tt: new n nn: new n i: new 2   while [nn >= i ^ 2][ if zero? nn % i [ while [zero? nn % i]-> 'nn / i 'tt - tt/i ] if i = 2 -> i: new 1   'i + 2 ] if nn > 1 -> 'tt - tt/nn   return tt ]   x: new 1 num: new 0   while [num < 20][ tot: new x s: new 0   while [tot <> 1][ tot: totient tot 's + tot ] if s = x [ prints ~"|x| " inc 'num ] 'x + 2 ] print ""
http://rosettacode.org/wiki/Perfect_totient_numbers
Perfect totient numbers
Generate and show here, the first twenty Perfect totient numbers. Related task   Totient function Also see   the OEIS entry for   perfect totient numbers.   mrob   list of the first 54
#AutoHotkey
AutoHotkey
MsgBox, 262144, , % result := perfect_totient(20)   perfect_totient(n){ count := sum := tot := 0, str:= "", m := 1 while (count < n) { tot := m, sum := 0 while (tot != 1) { tot := totient(tot) sum += tot } if (sum = m) { str .= m ", " count++ } m++ } return Trim(str, ", ") }   totient(n) { tot := n, i := 2 while (i*i <= n) { if !Mod(n, i) { while !Mod(n, i) n /= i tot -= tot / i } if (i = 2) i := 1 i+=2 } if (n > 1) tot -= tot / n return tot }
http://rosettacode.org/wiki/Playing_cards
Playing cards
Task Create a data structure and the associated methods to define and manipulate a deck of   playing cards. The deck should contain 52 unique cards. The methods must include the ability to:   make a new deck   shuffle (randomize) the deck   deal from the deck   print the current contents of a deck Each card must have a pip value and a suit value which constitute the unique value of the card. Related tasks: Card shuffles Deal cards_for_FreeCell War Card_Game Poker hand_analyser Go Fish
#Common_Lisp
Common Lisp
(defconstant +suits+ '(club diamond heart spade) "Card suits are the symbols club, diamond, heart, and spade.")   (defconstant +pips+ '(ace 2 3 4 5 6 7 8 9 10 jack queen king) "Card pips are the numbers 2 through 10, and the symbols ace, jack, queen and king.")   (defun make-deck (&aux (deck '())) "Returns a list of cards, where each card is a cons whose car is a suit and whose cdr is a pip." (dolist (suit +suits+ deck) (dolist (pip +pips+) (push (cons suit pip) deck))))   (defun shuffle (list) "Returns a shuffling of list, by sorting it with a random predicate. List may be modified." (sort list #'(lambda (x y) (declare (ignore x y)) (zerop (random 2)))))
http://rosettacode.org/wiki/Pi
Pi
Create a program to continually calculate and output the next decimal digit of   π {\displaystyle \pi }   (pi). The program should continue forever (until it is aborted by the user) calculating and outputting each decimal digit in succession. The output should be a decimal sequence beginning   3.14159265 ... Note: this task is about   calculating   pi.   For information on built-in pi constants see Real constants and functions. Related Task Arithmetic-geometric mean/Calculate Pi
#Clojure
Clojure
(ns pidigits (:gen-class))   (def calc-pi ; integer division rounding downwards to -infinity (let [div (fn [x y] (long (Math/floor (/ x y))))   ; Computations performed after yield clause in Python code update-after-yield (fn [[q r t k n l]] (let [nr (* 10 (- r (* n t))) nn (- (div (* 10 (+ (* 3 q) r)) t) (* 10 n)) nq (* 10 q)] [nq nr t k nn l]))   ; Update of else clause in Python code: if (< (- (+ (* 4 q) r) t) (* n t)) update-else (fn [[q r t k n l]] (let [nr (* (+ (* 2 q) r) l) nn (div (+ (* q 7 k) 2 (* r l)) (* t l)) nq (* k q) nt (* l t) nl (+ 2 l) nk (+ 1 k)] [nq nr nt nk nn nl]))   ; Compute the lazy sequence of pi digits translating the Python code pi-from (fn pi-from [[q r t k n l]] (if (< (- (+ (* 4 q) r) t) (* n t)) (lazy-seq (cons n (pi-from (update-after-yield [q r t k n l])))) (recur (update-else [q r t k n l]))))]   ; Use Clojure big numbers to perform the math (avoid integer overflow) (pi-from [1N 0N 1N 1N 3N 3N])))   ;; Indefinitely Output digits of pi, with 40 characters per line (doseq [[i q] (map-indexed vector calc-pi)] (when (= (mod i 40) 0) (println)) (print q))  
http://rosettacode.org/wiki/Periodic_table
Periodic table
Task Display the row and column in the periodic table of the given atomic number. The periodic table Let us consider the following periodic table representation. __________________________________________________________________________ | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | | | |1 H He | | | |2 Li Be B C N O F Ne | | | |3 Na Mg Al Si P S Cl Ar | | | |4 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr | | | |5 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe | | | |6 Cs Ba * Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn | | | |7 Fr Ra ° Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og | |__________________________________________________________________________| | | | | |8 Lantanoidi* La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu | | | |9 Aktinoidi° Ak Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr | |__________________________________________________________________________| Example test cases;   1 -> 1 1   2 -> 1 18   29 -> 4 11   42 -> 5 6   57 -> 8 4   58 -> 8 5   72 -> 6 4   89 -> 9 4 Details; The representation of the periodic table may be represented in various way. The one presented in this challenge does have the following property : Lantanides and Aktinoides are all in a dedicated row, hence there is no element that is placed at 6, 3 nor 7, 3. You may take a look at the atomic number repartitions here. The atomic number is at least 1, at most 118. See also   the periodic table   This task was an idea from CompSciFact   The periodic table in ascii that was used as template
#J
J
PT=: (' ',.~[;._2) {{)n 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 1 H He 2 Li Be B C N O F Ne 3 Na Mg Al Si P S Cl Ar 4 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 5 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe 6 Cs Ba * Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn 7 Fr Ra - Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og 8 Lantanoidi* La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu 9 Aktinoidi- Ak Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr }}   ptrc=: {{ tokens=. (#~ (3>#)@> * */@(tolower~:toupper)@>) ~.,;:,PT ndx=. (>' ',L:0' ',L:0~tokens) {.@I.@E."1 ,PT Lantanoidi=. ndx{+/\'*'=,PT Aktinoidi=. ndx{+/\'-'=,PT j=. 13|3*Lantanoidi+3*Aktinoidi k=. {:$PT 0,}."1/:~j,.(<.ndx%k),.1+(/:~@~. i. ])k|ndx }}   rowcol=: ptrc''
http://rosettacode.org/wiki/Periodic_table
Periodic table
Task Display the row and column in the periodic table of the given atomic number. The periodic table Let us consider the following periodic table representation. __________________________________________________________________________ | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | | | |1 H He | | | |2 Li Be B C N O F Ne | | | |3 Na Mg Al Si P S Cl Ar | | | |4 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr | | | |5 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe | | | |6 Cs Ba * Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn | | | |7 Fr Ra ° Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og | |__________________________________________________________________________| | | | | |8 Lantanoidi* La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu | | | |9 Aktinoidi° Ak Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr | |__________________________________________________________________________| Example test cases;   1 -> 1 1   2 -> 1 18   29 -> 4 11   42 -> 5 6   57 -> 8 4   58 -> 8 5   72 -> 6 4   89 -> 9 4 Details; The representation of the periodic table may be represented in various way. The one presented in this challenge does have the following property : Lantanides and Aktinoides are all in a dedicated row, hence there is no element that is placed at 6, 3 nor 7, 3. You may take a look at the atomic number repartitions here. The atomic number is at least 1, at most 118. See also   the periodic table   This task was an idea from CompSciFact   The periodic table in ascii that was used as template
#Julia
Julia
const limits = [3:10, 11:18, 19:36, 37:54, 55:86, 87:118]   function periodic_table(n) (n < 1 || n > 118) && error("Atomic number is out of range.") n == 1 && return [1, 1] n == 2 && return [1, 18] 57 <= n <= 71 && return [8, n - 53] 89 <= n <= 103 && return [9, n - 85] row, limitstart, limitstop = 0, 0, 0 for i in eachindex(limits) if limits[i].start <= n <= limits[i].stop row, limitstart, limitstop = i + 1, limits[i].start, limits[i].stop break end end return (n < limitstart + 2 || row == 4 || row == 5) ? [row, n - limitstart + 1] : [row, n - limitstop + 18] end   for n in [1, 2, 29, 42, 57, 58, 59, 71, 72, 89, 90, 103, 113] rc = periodic_table(n) println("Atomic number ", lpad(n, 3), " -> ($(rc[1]), $(rc[2]))") end  
http://rosettacode.org/wiki/Pig_the_dice_game
Pig the dice game
The   game of Pig   is a multiplayer game played with a single six-sided die.   The object of the game is to reach   100   points or more.   Play is taken in turns.   On each person's turn that person has the option of either: Rolling the dice:   where a roll of two to six is added to their score for that turn and the player's turn continues as the player is given the same choice again;   or a roll of   1   loses the player's total points   for that turn   and their turn finishes with play passing to the next player. Holding:   the player's score for that round is added to their total and becomes safe from the effects of throwing a   1   (one).   The player's turn finishes with play passing to the next player. Task Create a program to score for, and simulate dice throws for, a two-person game. Related task   Pig the dice game/Player
#J
J
require'general/misc/prompt' NB. was require'misc' in j6   status=:3 :0 'pid cur tot'=. y player=. 'player ',":pid potential=. ' potential: ',":cur total=. ' total: ',":tot smoutput player,potential,total )   getmove=:3 :0 whilst.1~:+/choice do. choice=.'HRQ' e. prompt '..Roll the dice or Hold or Quit? [R or H or Q]: ' end. choice#'HRQ' )   NB. simulate an y player game of pig pigsim=:3 :0 smoutput (":y),' player game of pig' scores=.y#0 while.100>>./scores do. for_player.=i.y do. smoutput 'begining of turn for player ',":pid=.1+I.player current=. 0 whilst. (1 ~: roll) *. 'R' = move do. status pid, current, player+/ .*scores if.'R'=move=. getmove'' do. smoutput 'rolled a ',":roll=. 1+?6 current=. (1~:roll)*current+roll end. end. scores=. scores+(current*player)+100*('Q'e.move)*-.player smoutput 'player scores now: ',":scores end. end. smoutput 'player ',(":1+I.scores>:100),' wins' )
http://rosettacode.org/wiki/Pernicious_numbers
Pernicious numbers
A   pernicious number   is a positive integer whose   population count   is a prime. The   population count   is the number of   ones   in the binary representation of a non-negative integer. Example 22   (which is   10110   in binary)   has a population count of   3,   which is prime,   and therefore 22   is a pernicious number. Task display the first   25   pernicious numbers   (in decimal). display all pernicious numbers between   888,888,877   and   888,888,888   (inclusive). display each list of integers on one line   (which may or may not include a title). See also Sequence   A052294 pernicious numbers on The On-Line Encyclopedia of Integer Sequences. Rosetta Code entry   population count, evil numbers, odious numbers.
#Common_Lisp
Common Lisp
(format T "~{~a ~}~%" (loop for n = 1 then (1+ n) when (primep (logcount n)) collect n into numbers when (= (length numbers) 25) return numbers))   (format T "~{~a ~}~%" (loop for n from 888888877 to 888888888 when (primep (logcount n)) collect n))
http://rosettacode.org/wiki/Permutations/Rank_of_a_permutation
Permutations/Rank of a permutation
A particular ranking of a permutation associates an integer with a particular ordering of all the permutations of a set of distinct items. For our purposes the ranking will assign integers 0.. ( n ! − 1 ) {\displaystyle 0..(n!-1)} to an ordering of all the permutations of the integers 0.. ( n − 1 ) {\displaystyle 0..(n-1)} . For example, the permutations of the digits zero to 3 arranged lexicographically have the following rank: PERMUTATION RANK (0, 1, 2, 3) -> 0 (0, 1, 3, 2) -> 1 (0, 2, 1, 3) -> 2 (0, 2, 3, 1) -> 3 (0, 3, 1, 2) -> 4 (0, 3, 2, 1) -> 5 (1, 0, 2, 3) -> 6 (1, 0, 3, 2) -> 7 (1, 2, 0, 3) -> 8 (1, 2, 3, 0) -> 9 (1, 3, 0, 2) -> 10 (1, 3, 2, 0) -> 11 (2, 0, 1, 3) -> 12 (2, 0, 3, 1) -> 13 (2, 1, 0, 3) -> 14 (2, 1, 3, 0) -> 15 (2, 3, 0, 1) -> 16 (2, 3, 1, 0) -> 17 (3, 0, 1, 2) -> 18 (3, 0, 2, 1) -> 19 (3, 1, 0, 2) -> 20 (3, 1, 2, 0) -> 21 (3, 2, 0, 1) -> 22 (3, 2, 1, 0) -> 23 Algorithms exist that can generate a rank from a permutation for some particular ordering of permutations, and that can generate the same rank from the given individual permutation (i.e. given a rank of 17 produce (2, 3, 1, 0) in the example above). One use of such algorithms could be in generating a small, random, sample of permutations of n {\displaystyle n} items without duplicates when the total number of permutations is large. Remember that the total number of permutations of n {\displaystyle n} items is given by n ! {\displaystyle n!} which grows large very quickly: A 32 bit integer can only hold 12 ! {\displaystyle 12!} , a 64 bit integer only 20 ! {\displaystyle 20!} . It becomes difficult to take the straight-forward approach of generating all permutations then taking a random sample of them. A question on the Stack Overflow site asked how to generate one million random and indivudual permutations of 144 items. Task Create a function to generate a permutation from a rank. Create the inverse function that given the permutation generates its rank. Show that for n = 3 {\displaystyle n=3} the two functions are indeed inverses of each other. Compute and show here 4 random, individual, samples of permutations of 12 objects. Stretch goal State how reasonable it would be to use your program to address the limits of the Stack Overflow question. References Ranking and Unranking Permutations in Linear Time by Myrvold & Ruskey. (Also available via Google here). Ranks on the DevData site. Another answer on Stack Overflow to a different question that explains its algorithm in detail. Related tasks Factorial_base_numbers_indexing_permutations_of_a_collection
#REXX
REXX
/*REXX program displays permutations of N number of objects (1, 2, 3, ···). */ parse arg N y seed . /*obtain optional arguments from the CL*/ if N=='' | N=="," then N= 4 /*Not specified? Then use the default.*/ if y=='' | y=="," then y= 17 /* " " " " " " */ if datatype(seed,'W') then call random ,,seed /*can make RANDOM numbers repeatable. */ permutes= permSets(N) /*returns N! (number of permutations).*/ w= length(permutes) /*used for aligning the SAY output. */ @.= do p=0 for permutes /*traipse through each of the permutes.*/ z= permSets(N, p) /*get which of the permutation it is.*/ say 'for' N "items, permute rank" right(p,w) 'is: ' z @.p= z /*define a rank permutation in @ array.*/ end /*p*/ say /* [↓] displays a particular perm rank*/ say ' the permutation rank of' y "is: " @.y /*display a particular permutation rank*/ exit /*stick a fork in it, we're all done. */ /*──────────────────────────────────────────────────────────────────────────────────────*/ permSets: procedure expose @. #; #= 0; parse arg x,r,c; c= space(c); xm= x -1 do j=1 for x; @.j= j-1; end /*j*/ _=0; do u=2 for xm; _= _ @.u; end /*u*/ if r==# then return _; if c==_ then return # do while .permSets(x,0); #= #+1; _= @.1 do v=2 for xm; _= _ @.v; end /*v*/ if r==# then return _; if c==_ then return # end /*while···*/ return #+1 /*──────────────────────────────────────────────────────────────────────────────────────*/ .permSets: procedure expose @.; parse arg p,q; pm= p-1 do k=pm by -1 for pm; kp= k+1; if @.k<@.kp then do; q=k; leave; end end /*k*/   do j=q+1 while j<p; parse value @.j @.p with @.p @.j; p= p-1 end /*j*/ if q==0 then return 0 do p=q+1 while @.p<@.q end /*p*/ parse value @.p @.q with @.q @.p return 1
http://rosettacode.org/wiki/Pierpont_primes
Pierpont primes
A Pierpont prime is a prime number of the form: 2u3v + 1 for some non-negative integers u and v . A Pierpont prime of the second kind is a prime number of the form: 2u3v - 1 for some non-negative integers u and v . The term "Pierpont primes" is generally understood to mean the first definition, but will be called "Pierpont primes of the first kind" on this page to distinguish them. Task Write a routine (function, procedure, whatever) to find Pierpont primes of the first & second kinds. Use the routine to find and display here, on this page, the first 50 Pierpont primes of the first kind. Use the routine to find and display here, on this page, the first 50 Pierpont primes of the second kind If your language supports large integers, find and display here, on this page, the 250th Pierpont prime of the first kind and the 250th Pierpont prime of the second kind. See also Wikipedia - Pierpont primes OEIS:A005109 - Class 1 -, or Pierpont primes OEIS:A005105 - Class 1 +, or Pierpont primes of the second kind
#Perl
Perl
use strict; use warnings; use feature 'say'; use bigint try=>"GMP"; use ntheory qw<is_prime>;   # index of mininum value in list sub min_index { my $b = $_[my $i = 0]; $_[$_] < $b && ($b = $_[$i = $_]) for 0..$#_; $i }   sub iter1 { my $m = shift; my $e = 0; return sub { $m ** $e++; } } sub iter2 { my $m = shift; my $e = 1; return sub { $m * ($e *= 2) } }   sub pierpont { my($max ) = shift || die 'Must specify count of primes to generate.'; my($kind) = @_ ? shift : 1; die "Unknown type: $kind. Must be one of 1 (default) or 2" unless $kind == 1 || $kind == 2; $kind = -1 if $kind == 2;   my $po3 = 3; my $add_one = 3; my @iterators; push @iterators, iter1(2); push @iterators, iter1(3); $iterators[1]->(); my @head = ($iterators[0]->(), $iterators[1]->());   my @pierpont; do { my $key = min_index(@head); my $min = $head[$key]; push @pierpont, $min + $kind if is_prime($min + $kind);   $head[$key] = $iterators[$key]->();   if ($min >= $add_one) { push @iterators, iter2($po3); $add_one = $head[$#iterators] = $iterators[$#iterators]->(); $po3 *= 3; } } until @pierpont == $max; @pierpont; }   my @pierpont_1st = pierpont(250,1); my @pierpont_2nd = pierpont(250,2);   say "First 50 Pierpont primes of the first kind:"; my $fmt = "%9d"x10 . "\n"; for my $row (0..4) { printf $fmt, map { $pierpont_1st[10*$row + $_] } 0..9 } say "\nFirst 50 Pierpont primes of the second kind:"; for my $row (0..4) { printf $fmt, map { $pierpont_2nd[10*$row + $_] } 0..9 }   say "\n250th Pierpont prime of the first kind: " . $pierpont_1st[249]; say "\n250th Pierpont prime of the second kind: " . $pierpont_2nd[249];
http://rosettacode.org/wiki/Pick_random_element
Pick random element
Demonstrate how to pick a random element from a list.
#Factor
Factor
( scratchpad ) { "a" "b" "c" "d" "e" "f" } random . "a"
http://rosettacode.org/wiki/Pick_random_element
Pick random element
Demonstrate how to pick a random element from a list.
#Falcon
Falcon
  lst = [1, 3, 5, 8, 10] > randomPick(lst)  
http://rosettacode.org/wiki/Primality_by_trial_division
Primality by trial division
Task Write a boolean function that tells whether a given integer is prime. Remember that   1   and all non-positive numbers are not prime. Use trial division. Even numbers greater than   2   may be eliminated right away. A loop from   3   to   √ n    will suffice,   but other loops are allowed. Related tasks   count in factors   prime decomposition   AKS test for primes   factors of an integer   Sieve of Eratosthenes   factors of a Mersenne number   trial factoring of a Mersenne number   partition an integer X into N primes   sequence of primes by Trial Division
#Ursala
Ursala
#import std #import nat   prime = ~<{0,1}&& -={2,3}!| ~&h&& (all remainder)^Dtt/~& iota@K31
http://rosettacode.org/wiki/Phrase_reversals
Phrase reversals
Task Given a string of space separated words containing the following phrase: rosetta code phrase reversal Reverse the characters of the string. Reverse the characters of each individual word in the string, maintaining original word order within the string. Reverse the order of each word of the string, maintaining the order of characters in each word. Show your output here. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#Factor
Factor
  USE: splitting   : splitp ( str -- seq ) " " split ; : printp ( seq -- ) " " join print ; : reverse-string ( str -- ) reverse print ; : reverse-words ( str -- ) splitp [ reverse ] map printp ; : reverse-phrase ( str -- ) splitp reverse printp ;   "rosetta code phrase reversal" [ reverse-string ] [ reverse-words ] [ reverse-phrase ] tri  
http://rosettacode.org/wiki/Phrase_reversals
Phrase reversals
Task Given a string of space separated words containing the following phrase: rosetta code phrase reversal Reverse the characters of the string. Reverse the characters of each individual word in the string, maintaining original word order within the string. Reverse the order of each word of the string, maintaining the order of characters in each word. Show your output here. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#Fortran
Fortran
DO WHILE (L1.LE.L .AND. ATXT(L1).LE." ") L1 = L1 + 1 END DO
http://rosettacode.org/wiki/Permutations/Derangements
Permutations/Derangements
A derangement is a permutation of the order of distinct items in which no item appears in its original place. For example, the only two derangements of the three items (0, 1, 2) are (1, 2, 0), and (2, 0, 1). The number of derangements of n distinct items is known as the subfactorial of n, sometimes written as !n. There are various ways to calculate !n. Task Create a named function/method/subroutine/... to generate derangements of the integers 0..n-1, (or 1..n if you prefer). Generate and show all the derangements of 4 integers using the above routine. Create a function that calculates the subfactorial of n, !n. Print and show a table of the counted number of derangements of n vs. the calculated !n for n from 0..9 inclusive. Optional stretch goal   Calculate    !20 Related tasks   Anagrams/Deranged anagrams   Best shuffle   Left_factorials Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#Clojure
Clojure
(ns derangements.core (:require [clojure.set :as s]))   (defn subfactorial [n] (case n 0 1 1 0 (* (dec n) (+ (subfactorial (dec n)) (subfactorial (- n 2))))))   (defn no-fixed-point "f : A -> B must be a biyective function written as a hash-map, returns all g : A -> B such that (f(a) = b) => not(g(a) = b)" [f] (case (count f) 0 [{}] 1 [] (let [g (s/map-invert f) a (first (keys f)) a' (f a)] (mapcat (fn [b'] (let [b (g b') f' (dissoc f a b)] (concat (map #(reduce conj % [[a b'] [b a']]) (no-fixed-point f')) (map #(conj % [a b']) (no-fixed-point (assoc f' b a')))))) (filter #(not= a' %) (keys g))))))   (defn derangements [xs] {:pre [(= (count xs) (count (set xs)))]} (map (fn [f] (mapv f xs)) (no-fixed-point (into {} (map vector xs xs)))))   (defn -main [] (do (doall (map println (derangements [0,1,2,3]))) (doall (map #(println (str (subfactorial %) " " (count (derangements (range %))))) (range 10))) (println (subfactorial 20))))  
http://rosettacode.org/wiki/Permutations_by_swapping
Permutations by swapping
Task Generate permutations of n items in which successive permutations differ from each other by the swapping of any two items. Also generate the sign of the permutation which is +1 when the permutation is generated from an even number of swaps from the initial state, and -1 for odd. Show the permutations and signs of three items, in order of generation here. Such data are of use in generating the determinant of a square matrix and any functions created should bear this in mind. Note: The Steinhaus–Johnson–Trotter algorithm generates successive permutations where adjacent items are swapped, but from this discussion adjacency is not a requirement. References Steinhaus–Johnson–Trotter algorithm Johnson-Trotter Algorithm Listing All Permutations Heap's algorithm [1] Tintinnalogia Related tasks   Matrix arithmetic   Gray code
#D
D
import std.algorithm, std.array, std.typecons, std.range;   struct Spermutations(bool doCopy=true) { private immutable uint n; alias TResult = Tuple!(int[], int);   int opApply(in int delegate(in ref TResult) nothrow dg) nothrow { int result;   int sign = 1; alias Int2 = Tuple!(int, int); auto p = n.iota.map!(i => Int2(i, i ? -1 : 0)).array; TResult aux;   aux[0] = p.map!(pi => pi[0]).array; aux[1] = sign; result = dg(aux); if (result) goto END;   while (p.any!q{ a[1] }) { // Failed to use std.algorithm here, too much complex. auto largest = Int2(-100, -100); int i1 = -1; foreach (immutable i, immutable pi; p) if (pi[1]) if (pi[0] > largest[0]) { i1 = i; largest = pi; } immutable n1 = largest[0], d1 = largest[1];   sign *= -1; int i2; if (d1 == -1) { i2 = i1 - 1; p[i1].swap(p[i2]); if (i2 == 0 || p[i2 - 1][0] > n1) p[i2][1] = 0; } else if (d1 == 1) { i2 = i1 + 1; p[i1].swap(p[i2]); if (i2 == n - 1 || p[i2 + 1][0] > n1) p[i2][1] = 0; }   if (doCopy) { aux[0] = p.map!(pi => pi[0]).array; } else { foreach (immutable i, immutable pi; p) aux[0][i] = pi[0]; } aux[1] = sign; result = dg(aux); if (result) goto END;   foreach (immutable i3, ref pi; p) { immutable n3 = pi[0], d3 = pi[1]; if (n3 > n1) pi[1] = (i3 < i2) ? 1 : -1; } }   END: return result; } }   Spermutations!doCopy spermutations(bool doCopy=true)(in uint n) { return typeof(return)(n); }   version (permutations_by_swapping1) { void main() { import std.stdio; foreach (immutable n; [3, 4]) { writefln("\nPermutations and sign of %d items", n); foreach (const tp; n.spermutations) writefln("Perm: %s Sign: %2d", tp[]); } } }
http://rosettacode.org/wiki/Permutation_test
Permutation test
Permutation test You are encouraged to solve this task according to the task description, using any language you may know. A new medical treatment was tested on a population of n + m {\displaystyle n+m} volunteers, with each volunteer randomly assigned either to a group of n {\displaystyle n} treatment subjects, or to a group of m {\displaystyle m} control subjects. Members of the treatment group were given the treatment, and members of the control group were given a placebo. The effect of the treatment or placebo on each volunteer was measured and reported in this table. Table of experimental results Treatment group Control group 85 68 88 41 75 10 66 49 25 16 29 65 83 32 39 92 97 28 98 Write a program that performs a permutation test to judge whether the treatment had a significantly stronger effect than the placebo. Do this by considering every possible alternative assignment from the same pool of volunteers to a treatment group of size n {\displaystyle n} and a control group of size m {\displaystyle m} (i.e., the same group sizes used in the actual experiment but with the group members chosen differently), while assuming that each volunteer's effect remains constant regardless. Note that the number of alternatives will be the binomial coefficient ( n + m n ) {\displaystyle {\tbinom {n+m}{n}}} . Compute the mean effect for each group and the difference in means between the groups in every case by subtracting the mean of the control group from the mean of the treatment group. Report the percentage of alternative groupings for which the difference in means is less or equal to the actual experimentally observed difference in means, and the percentage for which it is greater. Note that they should sum to 100%. Extremely dissimilar values are evidence of an effect not entirely due to chance, but your program need not draw any conclusions. You may assume the experimental data are known at compile time if that's easier than loading them at run time. Test your solution on the data given above.
#FreeBASIC
FreeBASIC
  Dim Shared datos(18) As Integer => {85, 88, 75, 66, 25, 29, 83, 39, 97,_ 68, 41, 10, 49, 16, 65, 32, 92, 28, 98}   Function pick(at As Integer, remain As Integer, accu As Integer, treat As Integer) As Integer If remain = 0 Then If accu > treat Then Return 1 Else Return 0 End If   Dim a As Integer If at > remain Then a = pick(at-1, remain, accu, treat) Else a = 0 Return pick(at-1, remain-1, accu+datos(at), treat) + a End Function   Dim As Integer treat = 0, le, gt, total = 1, i   For i = 1 To 9 treat += datos(i) Next i For i = 19 To 11 Step -1 total *= i Next i For i = 9 To 1 Step -1 total /= i Next i   gt = pick(19, 9, 0, treat) le = total - gt   Print Using "<= : ##.######% #####"; 100*le/total; le Print Using " > : ##.######% #####"; 100*gt/total; gt Sleep  
http://rosettacode.org/wiki/Percolation/Mean_run_density
Percolation/Mean run density
Percolation Simulation This is a simulation of aspects of mathematical percolation theory. For other percolation simulations, see Category:Percolation Simulations, or: 1D finite grid simulation Mean run density 2D finite grid simulations Site percolation | Bond percolation | Mean cluster density Let v {\displaystyle v} be a vector of n {\displaystyle n} values of either 1 or 0 where the probability of any value being 1 is p {\displaystyle p} ; the probability of a value being 0 is therefore 1 − p {\displaystyle 1-p} . Define a run of 1s as being a group of consecutive 1s in the vector bounded either by the limits of the vector or by a 0. Let the number of such runs in a given vector of length n {\displaystyle n} be R n {\displaystyle R_{n}} . For example, the following vector has R 10 = 3 {\displaystyle R_{10}=3} [1 1 0 0 0 1 0 1 1 1] ^^^ ^ ^^^^^ Percolation theory states that K ( p ) = lim n → ∞ R n / n = p ( 1 − p ) {\displaystyle K(p)=\lim _{n\to \infty }R_{n}/n=p(1-p)} Task Any calculation of R n / n {\displaystyle R_{n}/n} for finite n {\displaystyle n} is subject to randomness so should be computed as the average of t {\displaystyle t} runs, where t ≥ 100 {\displaystyle t\geq 100} . For values of p {\displaystyle p} of 0.1, 0.3, 0.5, 0.7, and 0.9, show the effect of varying n {\displaystyle n} on the accuracy of simulated K ( p ) {\displaystyle K(p)} . Show your output here. See also s-Run on Wolfram mathworld.
#C
C
#include <stdio.h> #include <stdlib.h>   // just generate 0s and 1s without storing them double run_test(double p, int len, int runs) { int r, x, y, i, cnt = 0, thresh = p * RAND_MAX;   for (r = 0; r < runs; r++) for (x = 0, i = len; i--; x = y) cnt += x < (y = rand() < thresh);   return (double)cnt / runs / len; }   int main(void) { double p, p1p, K; int ip, n;   puts( "running 1000 tests each:\n" " p\t n\tK\tp(1-p)\t diff\n" "-----------------------------------------------"); for (ip = 1; ip < 10; ip += 2) { p = ip / 10., p1p = p * (1 - p);   for (n = 100; n <= 100000; n *= 10) { K = run_test(p, n, 1000); printf("%.1f\t%6d\t%.4f\t%.4f\t%+.4f (%+.2f%%)\n", p, n, K, p1p, K - p1p, (K - p1p) / p1p * 100); } putchar('\n'); }   return 0; }
http://rosettacode.org/wiki/Percolation/Site_percolation
Percolation/Site percolation
Percolation Simulation This is a simulation of aspects of mathematical percolation theory. For other percolation simulations, see Category:Percolation Simulations, or: 1D finite grid simulation Mean run density 2D finite grid simulations Site percolation | Bond percolation | Mean cluster density Given an M × N {\displaystyle M\times N} rectangular array of cells numbered c e l l [ 0.. M − 1 , 0.. N − 1 ] {\displaystyle \mathrm {cell} [0..M-1,0..N-1]} assume M {\displaystyle M} is horizontal and N {\displaystyle N} is downwards. Assume that the probability of any cell being filled is a constant p {\displaystyle p} where 0.0 ≤ p ≤ 1.0 {\displaystyle 0.0\leq p\leq 1.0} The task Simulate creating the array of cells with probability p {\displaystyle p} and then testing if there is a route through adjacent filled cells from any on row 0 {\displaystyle 0} to any on row N {\displaystyle N} , i.e. testing for site percolation. Given p {\displaystyle p} repeat the percolation t {\displaystyle t} times to estimate the proportion of times that the fluid can percolate to the bottom for any given p {\displaystyle p} . Show how the probability of percolating through the random grid changes with p {\displaystyle p} going from 0.0 {\displaystyle 0.0} to 1.0 {\displaystyle 1.0} in 0.1 {\displaystyle 0.1} increments and with the number of repetitions to estimate the fraction at any given p {\displaystyle p} as t >= 100 {\displaystyle t>=100} . Use an M = 15 , N = 15 {\displaystyle M=15,N=15} grid of cells for all cases. Optionally depict a percolation through a cell grid graphically. Show all output on this page.
#C
C
#include <stdio.h> #include <stdlib.h> #include <string.h>   char *cell, *start, *end; int m, n;   void make_grid(int x, int y, double p) { int i, j, thresh = p * RAND_MAX;   m = x, n = y; end = start = realloc(start, (x+1) * (y+1) + 1);   memset(start, 0, m + 1);   cell = end = start + m + 1; for (i = 0; i < n; i++) { for (j = 0; j < m; j++) *end++ = rand() < thresh ? '+' : '.'; *end++ = '\n'; }   end[-1] = 0; end -= ++m; // end is the first cell of bottom row }   int ff(char *p) // flood fill { if (*p != '+') return 0;   *p = '#'; return p >= end || ff(p+m) || ff(p+1) || ff(p-1) || ff(p-m); }   int percolate(void) { int i; for (i = 0; i < m && !ff(cell + i); i++); return i < m; }   int main(void) { make_grid(15, 15, .5); percolate();   puts("15x15 grid:"); puts(cell);   puts("\nrunning 10,000 tests for each case:");   double p; int ip, i, cnt; for (ip = 0; ip <= 10; ip++) { p = ip / 10.; for (cnt = i = 0; i < 10000; i++) { make_grid(15, 15, p); cnt += percolate(); } printf("p=%.1f:  %.4f\n", p, cnt / 10000.); }   return 0; }
http://rosettacode.org/wiki/Permutations
Permutations
Task Write a program that generates all   permutations   of   n   different objects.   (Practically numerals!) Related tasks   Find the missing permutation   Permutations/Derangements The number of samples of size k from n objects. With   combinations and permutations   generation tasks. Order Unimportant Order Important Without replacement ( n k ) = n C k = n ( n − 1 ) … ( n − k + 1 ) k ( k − 1 ) … 1 {\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}} n P k = n ⋅ ( n − 1 ) ⋅ ( n − 2 ) ⋯ ( n − k + 1 ) {\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)} Task: Combinations Task: Permutations With replacement ( n + k − 1 k ) = n + k − 1 C k = ( n + k − 1 ) ! ( n − 1 ) ! k ! {\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}} n k {\displaystyle n^{k}} Task: Combinations with repetitions Task: Permutations with repetitions
#11l
11l
V a = [1, 2, 3] L print(a) I !a.next_permutation() L.break
http://rosettacode.org/wiki/Perfect_shuffle
Perfect shuffle
A perfect shuffle (or faro/weave shuffle) means splitting a deck of cards into equal halves, and perfectly interleaving them - so that you end up with the first card from the left half, followed by the first card from the right half, and so on: 7♠ 8♠ 9♠ J♠ Q♠ K♠→7♠  8♠  9♠   J♠  Q♠  K♠→7♠ J♠ 8♠ Q♠ 9♠ K♠ When you repeatedly perform perfect shuffles on an even-sized deck of unique cards, it will at some point arrive back at its original order. How many shuffles this takes, depends solely on the number of cards in the deck - for example for a deck of eight cards it takes three shuffles: original: 1 2 3 4 5 6 7 8 after 1st shuffle: 1 5 2 6 3 7 4 8 after 2nd shuffle: 1 3 5 7 2 4 6 8 after 3rd shuffle: 1 2 3 4 5 6 7 8 The Task Write a function that can perform a perfect shuffle on an even-sized list of values. Call this function repeatedly to count how many shuffles are needed to get a deck back to its original order, for each of the deck sizes listed under "Test Cases" below. You can use a list of numbers (or anything else that's convenient) to represent a deck; just make sure that all "cards" are unique within each deck. Print out the resulting shuffle counts, to demonstrate that your program passes the test-cases. Test Cases input (deck size) output (number of shuffles required) 8 3 24 11 52 8 100 30 1020 1018 1024 10 10000 300
#11l
11l
F flatten(lst) [Int] r L(sublst) lst L(i) sublst r [+]= i R r   F magic_shuffle(deck) V half = deck.len I/ 2 R flatten(zip(deck[0 .< half], deck[half ..]))   F after_how_many_is_equal(start, end) V deck = magic_shuffle(start) V counter = 1 L deck != end deck = magic_shuffle(deck) counter++ R counter   print(‘Length of the deck of cards | Perfect shuffles needed to obtain the same deck back’) L(length) (8, 24, 52, 100, 1020, 1024, 10000) V deck = Array(0 .< length) V shuffles_needed = after_how_many_is_equal(deck, deck) print(‘#<5 | #.’.format(length, shuffles_needed))
http://rosettacode.org/wiki/Perlin_noise
Perlin noise
The   Perlin noise   is a kind of   gradient noise   invented by   Ken Perlin   around the end of the twentieth century and still currently heavily used in   computer graphics,   most notably to procedurally generate textures or heightmaps. The Perlin noise is basically a   pseudo-random   mapping of   R d {\displaystyle \mathbb {R} ^{d}}   into   R {\displaystyle \mathbb {R} }   with an integer   d {\displaystyle d}   which can be arbitrarily large but which is usually   2,   3,   or   4. Either by using a dedicated library or by implementing the algorithm, show that the Perlin noise   (as defined in 2002 in the Java implementation below)   of the point in 3D-space with coordinates     3.14,   42,   7     is     0.13691995878400012. Note: this result assumes 64 bit IEEE-754 floating point calculations. If your language uses a different floating point representation, make a note of it and calculate the value accurate to 15 decimal places, or your languages accuracy threshold if it is less. Trailing zeros need not be displayed.
#D
D
import std.stdio, std.math;   struct PerlinNoise { private static double fade(in double t) pure nothrow @safe @nogc { return t ^^ 3 * (t * (t * 6 - 15) + 10); }   private static double lerp(in double t, in double a, in double b) pure nothrow @safe @nogc { return a + t * (b - a); }   private static double grad(in ubyte hash, in double x, in double y, in double z) pure nothrow @safe @nogc { // Convert lo 4 bits of hash code into 12 gradient directions. immutable h = hash & 0xF; immutable double u = (h < 8) ? x : y, v = (h < 4) ? y : (h == 12 || h == 14 ? x : z); return ((h & 1) == 0 ? u : -u) + ((h & 2) == 0 ? v : -v); }   static immutable ubyte[512] p;   static this() pure nothrow @safe @nogc { static immutable permutation = cast(ubyte[256])x"97 A0 89 5B 5A 0F 83 0D C9 5F 60 35 C2 E9 07 E1 8C 24 67 1E 45 8E 08 63 25 F0 15 0A 17 BE 06 94 F7 78 EA 4B 00 1A C5 3E 5E FC DB CB 75 23 0B 20 39 B1 21 58 ED 95 38 57 AE 14 7D 88 AB A8 44 AF 4A A5 47 86 8B 30 1B A6 4D 92 9E E7 53 6F E5 7A 3C D3 85 E6 DC 69 5C 29 37 2E F5 28 F4 66 8F 36 41 19 3F A1 01 D8 50 49 D1 4C 84 BB D0 59 12 A9 C8 C4 87 82 74 BC 9F 56 A4 64 6D C6 AD BA 03 40 34 D9 E2 FA 7C 7B 05 CA 26 93 76 7E FF 52 55 D4 CF CE 3B E3 2F 10 3A 11 B6 BD 1C 2A DF B7 AA D5 77 F8 98 02 2C 9A A3 46 DD 99 65 9B A7 2B AC 09 81 16 27 FD 13 62 6C 6E 4F 71 E0 E8 B2 B9 70 68 DA F6 61 E4 FB 22 F2 C1 EE D2 90 0C BF B3 A2 F1 51 33 91 EB F9 0E EF 6B 31 C0 D6 1F B5 C7 6A 9D B8 54 CC B0 73 79 32 2D 7F 04 96 FE 8A EC CD 5D DE 72 43 1D 18 48 F3 8D 80 C3 4E 42 D7 3D 9C B4";   // Two copies of permutation. p[0 .. permutation.length] = permutation[]; p[permutation.length .. $] = permutation[]; }   /// x0, y0 and z0 can be any real numbers, but the result is /// zero if they are all integers. /// The result is probably in [-1.0, 1.0]. static double opCall(in double x0, in double y0, in double z0) pure nothrow @safe @nogc { // Find unit cube that contains point. immutable ubyte X = cast(int)x0.floor & 0xFF, Y = cast(int)y0.floor & 0xFF, Z = cast(int)z0.floor & 0xFF;   // Find relative x,y,z of point in cube. immutable x = x0 - x0.floor, y = y0 - y0.floor, z = z0 - z0.floor;   // Compute fade curves for each of x,y,z. immutable u = fade(x), v = fade(y), w = fade(z);   // Hash coordinates of the 8 cube corners. immutable A = p[X ] + Y, AA = p[A] + Z, AB = p[A + 1] + Z, B = p[X + 1] + Y, BA = p[B] + Z, BB = p[B + 1] + Z;   // And add blended results from 8 corners of cube. return lerp(w, lerp(v, lerp(u, grad(p[AA ], x , y , z ), grad(p[BA ], x-1, y , z )), lerp(u, grad(p[AB ], x , y-1, z ), grad(p[BB ], x-1, y-1, z ))), lerp(v, lerp(u, grad(p[AA+1], x , y , z-1), grad(p[BA+1], x-1, y , z-1)), lerp(u, grad(p[AB+1], x , y-1, z-1), grad(p[BB+1], x-1, y-1, z-1)))); } }   void main() { writefln("%1.17f", PerlinNoise(3.14, 42, 7));   /* // Generate a demo image using the Gray Scale task module. import grayscale_image; enum N = 200; auto im = new Image!Gray(N, N); foreach (immutable y; 0 .. N) foreach (immutable x; 0 .. N) { immutable p = PerlinNoise(x / 30.0, y / 30.0, 0.1); im[x, y] = Gray(cast(ubyte)((p + 1) / 2 * 256)); } im.savePGM("perlin_noise.pgm"); */ }
http://rosettacode.org/wiki/Perfect_totient_numbers
Perfect totient numbers
Generate and show here, the first twenty Perfect totient numbers. Related task   Totient function Also see   the OEIS entry for   perfect totient numbers.   mrob   list of the first 54
#AWK
AWK
  # syntax: GAWK -f PERFECT_TOTIENT_NUMBERS.AWK BEGIN { i = 20 printf("The first %d perfect totient numbers:\n%s\n",i,perfect_totient(i)) exit(0) } function perfect_totient(n, count,m,str,sum,tot) { for (m=1; count<n; m++) { tot = m sum = 0 while (tot != 1) { tot = totient(tot) sum += tot } if (sum == m) { str = str m " " count++ } } return(str) } function totient(n, i,tot) { tot = n for (i=2; i*i<=n; i+=2) { if (n % i == 0) { while (n % i == 0) { n /= i } tot -= tot / i } if (i == 2) { i = 1 } } if (n > 1) { tot -= tot / n } return(tot) }  
http://rosettacode.org/wiki/Perfect_totient_numbers
Perfect totient numbers
Generate and show here, the first twenty Perfect totient numbers. Related task   Totient function Also see   the OEIS entry for   perfect totient numbers.   mrob   list of the first 54
#BASIC
BASIC
10 DEFINT A-Z 20 N=3 30 S=N: T=0 40 X=S: S=0 50 FOR I=1 TO X-1 60 A=X: B=I 70 IF B>0 THEN C=A: A=B: B=C MOD B: GOTO 70 80 IF A=1 THEN S=S+1 90 NEXT 100 T=T+S 110 IF S>1 GOTO 40 120 IF T=N THEN PRINT N,: Z=Z+1 130 N=N+2 140 IF Z<20 GOTO 30
http://rosettacode.org/wiki/Playing_cards
Playing cards
Task Create a data structure and the associated methods to define and manipulate a deck of   playing cards. The deck should contain 52 unique cards. The methods must include the ability to:   make a new deck   shuffle (randomize) the deck   deal from the deck   print the current contents of a deck Each card must have a pip value and a suit value which constitute the unique value of the card. Related tasks: Card shuffles Deal cards_for_FreeCell War Card_Game Poker hand_analyser Go Fish
#D
D
import std.stdio, std.typecons, std.algorithm, std.traits, std.array, std.range, std.random;   enum Pip {Two, Three, Four, Five, Six, Seven, Eight, Nine, Ten, Jack, Queen, King, Ace} enum Suit {Diamonds, Spades, Hearts, Clubs} alias Card = Tuple!(Pip, Suit);   auto newDeck() pure nothrow @safe { return cartesianProduct([EnumMembers!Pip], [EnumMembers!Suit]); }   alias shuffleDeck = randomShuffle;   Card dealCard(ref Card[] deck) pure nothrow @safe @nogc { immutable card = deck.back; deck.popBack; return card; }   void show(in Card[] deck) @safe { writefln("Deck:\n%(%s\n%)\n", deck); }   void main() /*@safe*/ { auto d = newDeck.array; d.show; d.shuffleDeck; while (!d.empty) d.dealCard.writeln; }
http://rosettacode.org/wiki/Pi
Pi
Create a program to continually calculate and output the next decimal digit of   π {\displaystyle \pi }   (pi). The program should continue forever (until it is aborted by the user) calculating and outputting each decimal digit in succession. The output should be a decimal sequence beginning   3.14159265 ... Note: this task is about   calculating   pi.   For information on built-in pi constants see Real constants and functions. Related Task Arithmetic-geometric mean/Calculate Pi
#Common_Lisp
Common Lisp
(defun pi-spigot () (labels ((g (q r t1 k n l) (cond ((< (- (+ (* 4 q) r) t1) (* n t1)) (princ n) (g (* 10 q) (* 10 (- r (* n t1))) t1 k (- (floor (/ (* 10 (+ (* 3 q) r)) t1)) (* 10 n)) l)) (t (g (* q k) (* (+ (* 2 q) r) l) (* t1 l) (+ k 1) (floor (/ (+ (* q (+ (* 7 k) 2)) (* r l)) (* t1 l))) (+ l 2)))))) (g 1 0 1 1 3 3)))
http://rosettacode.org/wiki/Periodic_table
Periodic table
Task Display the row and column in the periodic table of the given atomic number. The periodic table Let us consider the following periodic table representation. __________________________________________________________________________ | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | | | |1 H He | | | |2 Li Be B C N O F Ne | | | |3 Na Mg Al Si P S Cl Ar | | | |4 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr | | | |5 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe | | | |6 Cs Ba * Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn | | | |7 Fr Ra ° Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og | |__________________________________________________________________________| | | | | |8 Lantanoidi* La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu | | | |9 Aktinoidi° Ak Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr | |__________________________________________________________________________| Example test cases;   1 -> 1 1   2 -> 1 18   29 -> 4 11   42 -> 5 6   57 -> 8 4   58 -> 8 5   72 -> 6 4   89 -> 9 4 Details; The representation of the periodic table may be represented in various way. The one presented in this challenge does have the following property : Lantanides and Aktinoides are all in a dedicated row, hence there is no element that is placed at 6, 3 nor 7, 3. You may take a look at the atomic number repartitions here. The atomic number is at least 1, at most 118. See also   the periodic table   This task was an idea from CompSciFact   The periodic table in ascii that was used as template
#Mathematica.2FWolfram_Language
Mathematica/Wolfram Language
ClearAll[FindPeriodGroup] FindPeriodGroup[n_Integer] := Which[57 <= n <= 70, {8, n - 53} , 89 <= n <= 102, {9, n - 85} , 1 <= n <= 118, {ElementData[n, "Period"], ElementData[n, "Group"]} , True, Missing["Element does not exist"] ] Row[{"Element ", #, " -> ", FindPeriodGroup[#]}] & /@ {1, 2, 29, 42, 57, 58, 59, 71, 72, 89, 90, 103, 113} // Column Graphics[Text[#, {1, -1} Reverse@FindPeriodGroup[#]] & /@ Range[118]]
http://rosettacode.org/wiki/Periodic_table
Periodic table
Task Display the row and column in the periodic table of the given atomic number. The periodic table Let us consider the following periodic table representation. __________________________________________________________________________ | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | | | |1 H He | | | |2 Li Be B C N O F Ne | | | |3 Na Mg Al Si P S Cl Ar | | | |4 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr | | | |5 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe | | | |6 Cs Ba * Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn | | | |7 Fr Ra ° Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og | |__________________________________________________________________________| | | | | |8 Lantanoidi* La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu | | | |9 Aktinoidi° Ak Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr | |__________________________________________________________________________| Example test cases;   1 -> 1 1   2 -> 1 18   29 -> 4 11   42 -> 5 6   57 -> 8 4   58 -> 8 5   72 -> 6 4   89 -> 9 4 Details; The representation of the periodic table may be represented in various way. The one presented in this challenge does have the following property : Lantanides and Aktinoides are all in a dedicated row, hence there is no element that is placed at 6, 3 nor 7, 3. You may take a look at the atomic number repartitions here. The atomic number is at least 1, at most 118. See also   the periodic table   This task was an idea from CompSciFact   The periodic table in ascii that was used as template
#Perl
Perl
use strict; use warnings; no warnings 'uninitialized'; use feature 'say'; use List::Util <sum head>;   sub divmod { int $_[0]/$_[1], $_[0]%$_[1] }   my $b = 18; my(@offset,@span,$cnt); push @span, ($cnt++) x $_ for <1 3 8 44 15 17 15 15>; @offset = (16, 10, 10, (2*$b)+1, (-2*$b)-15, (2*$b)+1, (-2*$b)-15);   for my $n (<1 2 29 42 57 58 72 89 90 103 118>) { printf "%3d: %2d, %2d\n", $n, map { $_+1 } divmod $n-1 + sum(head $span[$n-1], @offset), $b; }
http://rosettacode.org/wiki/Pig_the_dice_game
Pig the dice game
The   game of Pig   is a multiplayer game played with a single six-sided die.   The object of the game is to reach   100   points or more.   Play is taken in turns.   On each person's turn that person has the option of either: Rolling the dice:   where a roll of two to six is added to their score for that turn and the player's turn continues as the player is given the same choice again;   or a roll of   1   loses the player's total points   for that turn   and their turn finishes with play passing to the next player. Holding:   the player's score for that round is added to their total and becomes safe from the effects of throwing a   1   (one).   The player's turn finishes with play passing to the next player. Task Create a program to score for, and simulate dice throws for, a two-person game. Related task   Pig the dice game/Player
#Java
Java
import java.util.*;   public class PigDice {   public static void main(String[] args) { final int maxScore = 100; final int playerCount = 2; final String[] yesses = {"y", "Y", ""};   int[] safeScore = new int[2]; int player = 0, score = 0;   Scanner sc = new Scanner(System.in); Random rnd = new Random();   while (true) { System.out.printf(" Player %d: (%d, %d) Rolling? (y/n) ", player, safeScore[player], score); if (safeScore[player] + score < maxScore && Arrays.asList(yesses).contains(sc.nextLine())) { final int rolled = rnd.nextInt(6) + 1; System.out.printf(" Rolled %d\n", rolled); if (rolled == 1) { System.out.printf(" Bust! You lose %d but keep %d\n\n", score, safeScore[player]); } else { score += rolled; continue; } } else { safeScore[player] += score; if (safeScore[player] >= maxScore) break; System.out.printf(" Sticking with %d\n\n", safeScore[player]); } score = 0; player = (player + 1) % playerCount; } System.out.printf("\n\nPlayer %d wins with a score of %d", player, safeScore[player]); } }
http://rosettacode.org/wiki/Pernicious_numbers
Pernicious numbers
A   pernicious number   is a positive integer whose   population count   is a prime. The   population count   is the number of   ones   in the binary representation of a non-negative integer. Example 22   (which is   10110   in binary)   has a population count of   3,   which is prime,   and therefore 22   is a pernicious number. Task display the first   25   pernicious numbers   (in decimal). display all pernicious numbers between   888,888,877   and   888,888,888   (inclusive). display each list of integers on one line   (which may or may not include a title). See also Sequence   A052294 pernicious numbers on The On-Line Encyclopedia of Integer Sequences. Rosetta Code entry   population count, evil numbers, odious numbers.
#D
D
void main() { import std.stdio, std.algorithm, std.range, core.bitop;   immutable pernicious = (in uint n) => (2 ^^ n.popcnt) & 0xA08A28AC; uint.max.iota.filter!pernicious.take(25).writeln; iota(888_888_877, 888_888_889).filter!pernicious.writeln; }
http://rosettacode.org/wiki/Permutations/Rank_of_a_permutation
Permutations/Rank of a permutation
A particular ranking of a permutation associates an integer with a particular ordering of all the permutations of a set of distinct items. For our purposes the ranking will assign integers 0.. ( n ! − 1 ) {\displaystyle 0..(n!-1)} to an ordering of all the permutations of the integers 0.. ( n − 1 ) {\displaystyle 0..(n-1)} . For example, the permutations of the digits zero to 3 arranged lexicographically have the following rank: PERMUTATION RANK (0, 1, 2, 3) -> 0 (0, 1, 3, 2) -> 1 (0, 2, 1, 3) -> 2 (0, 2, 3, 1) -> 3 (0, 3, 1, 2) -> 4 (0, 3, 2, 1) -> 5 (1, 0, 2, 3) -> 6 (1, 0, 3, 2) -> 7 (1, 2, 0, 3) -> 8 (1, 2, 3, 0) -> 9 (1, 3, 0, 2) -> 10 (1, 3, 2, 0) -> 11 (2, 0, 1, 3) -> 12 (2, 0, 3, 1) -> 13 (2, 1, 0, 3) -> 14 (2, 1, 3, 0) -> 15 (2, 3, 0, 1) -> 16 (2, 3, 1, 0) -> 17 (3, 0, 1, 2) -> 18 (3, 0, 2, 1) -> 19 (3, 1, 0, 2) -> 20 (3, 1, 2, 0) -> 21 (3, 2, 0, 1) -> 22 (3, 2, 1, 0) -> 23 Algorithms exist that can generate a rank from a permutation for some particular ordering of permutations, and that can generate the same rank from the given individual permutation (i.e. given a rank of 17 produce (2, 3, 1, 0) in the example above). One use of such algorithms could be in generating a small, random, sample of permutations of n {\displaystyle n} items without duplicates when the total number of permutations is large. Remember that the total number of permutations of n {\displaystyle n} items is given by n ! {\displaystyle n!} which grows large very quickly: A 32 bit integer can only hold 12 ! {\displaystyle 12!} , a 64 bit integer only 20 ! {\displaystyle 20!} . It becomes difficult to take the straight-forward approach of generating all permutations then taking a random sample of them. A question on the Stack Overflow site asked how to generate one million random and indivudual permutations of 144 items. Task Create a function to generate a permutation from a rank. Create the inverse function that given the permutation generates its rank. Show that for n = 3 {\displaystyle n=3} the two functions are indeed inverses of each other. Compute and show here 4 random, individual, samples of permutations of 12 objects. Stretch goal State how reasonable it would be to use your program to address the limits of the Stack Overflow question. References Ranking and Unranking Permutations in Linear Time by Myrvold & Ruskey. (Also available via Google here). Ranks on the DevData site. Another answer on Stack Overflow to a different question that explains its algorithm in detail. Related tasks Factorial_base_numbers_indexing_permutations_of_a_collection
#Ring
Ring
  # Project : Permutations/Rank of a permutation   list = [0, 1, 2, 3] for perm = 0 to 23 str = "" for i = 1 to len(list) str = str + list[i] + ", " next see nl str = left(str, len(str)-2) see "(" + str + ") -> " + perm nextPermutation(list) next   func nextPermutation(a) elementcount = len(a) if elementcount < 1 then return ok pos = elementcount-1 while a[pos] >= a[pos+1] pos -= 1 if pos <= 0 permutationReverse(a, 1, elementcount) return ok end last = elementcount while a[last] <= a[pos] last -= 1 end temp = a[pos] a[pos] = a[last] a[last] = temp permutationReverse(a, pos+1, elementcount)   func permutationReverse(a, first, last) while first < last temp = a[first] a[first] = a[last] a[last] = temp first = first + 1 last = last - 1 end  
http://rosettacode.org/wiki/Permutations/Rank_of_a_permutation
Permutations/Rank of a permutation
A particular ranking of a permutation associates an integer with a particular ordering of all the permutations of a set of distinct items. For our purposes the ranking will assign integers 0.. ( n ! − 1 ) {\displaystyle 0..(n!-1)} to an ordering of all the permutations of the integers 0.. ( n − 1 ) {\displaystyle 0..(n-1)} . For example, the permutations of the digits zero to 3 arranged lexicographically have the following rank: PERMUTATION RANK (0, 1, 2, 3) -> 0 (0, 1, 3, 2) -> 1 (0, 2, 1, 3) -> 2 (0, 2, 3, 1) -> 3 (0, 3, 1, 2) -> 4 (0, 3, 2, 1) -> 5 (1, 0, 2, 3) -> 6 (1, 0, 3, 2) -> 7 (1, 2, 0, 3) -> 8 (1, 2, 3, 0) -> 9 (1, 3, 0, 2) -> 10 (1, 3, 2, 0) -> 11 (2, 0, 1, 3) -> 12 (2, 0, 3, 1) -> 13 (2, 1, 0, 3) -> 14 (2, 1, 3, 0) -> 15 (2, 3, 0, 1) -> 16 (2, 3, 1, 0) -> 17 (3, 0, 1, 2) -> 18 (3, 0, 2, 1) -> 19 (3, 1, 0, 2) -> 20 (3, 1, 2, 0) -> 21 (3, 2, 0, 1) -> 22 (3, 2, 1, 0) -> 23 Algorithms exist that can generate a rank from a permutation for some particular ordering of permutations, and that can generate the same rank from the given individual permutation (i.e. given a rank of 17 produce (2, 3, 1, 0) in the example above). One use of such algorithms could be in generating a small, random, sample of permutations of n {\displaystyle n} items without duplicates when the total number of permutations is large. Remember that the total number of permutations of n {\displaystyle n} items is given by n ! {\displaystyle n!} which grows large very quickly: A 32 bit integer can only hold 12 ! {\displaystyle 12!} , a 64 bit integer only 20 ! {\displaystyle 20!} . It becomes difficult to take the straight-forward approach of generating all permutations then taking a random sample of them. A question on the Stack Overflow site asked how to generate one million random and indivudual permutations of 144 items. Task Create a function to generate a permutation from a rank. Create the inverse function that given the permutation generates its rank. Show that for n = 3 {\displaystyle n=3} the two functions are indeed inverses of each other. Compute and show here 4 random, individual, samples of permutations of 12 objects. Stretch goal State how reasonable it would be to use your program to address the limits of the Stack Overflow question. References Ranking and Unranking Permutations in Linear Time by Myrvold & Ruskey. (Also available via Google here). Ranks on the DevData site. Another answer on Stack Overflow to a different question that explains its algorithm in detail. Related tasks Factorial_base_numbers_indexing_permutations_of_a_collection
#Ruby
Ruby
class Permutation include Enumerable attr_reader :num_elements, :size   def initialize(num_elements) @num_elements = num_elements @size = fact(num_elements) end   def each return self.to_enum unless block_given? (0...@size).each{|i| yield unrank(i)} end   def unrank(r) # nonrecursive version of Myrvold Ruskey unrank2 algorithm. pi = (0...num_elements).to_a (@num_elements-1).downto(1) do |n| s, r = r.divmod(fact(n)) pi[n], pi[s] = pi[s], pi[n] end pi end   def rank(pi) # nonrecursive version of Myrvold Ruskey rank2 algorithm. pi = pi.dup pi1 = pi.zip(0...pi.size).sort.map(&:last) (pi.size-1).downto(0).inject(0) do |memo,i| pi[i], pi[pi1[i]] = pi[pi1[i]], (s = pi[i]) pi1[s], pi1[i] = pi1[i], pi1[s] memo += s * fact(i) end end   private def fact(n) n.zero? ? 1 : n.downto(1).inject(:*) end end
http://rosettacode.org/wiki/Pierpont_primes
Pierpont primes
A Pierpont prime is a prime number of the form: 2u3v + 1 for some non-negative integers u and v . A Pierpont prime of the second kind is a prime number of the form: 2u3v - 1 for some non-negative integers u and v . The term "Pierpont primes" is generally understood to mean the first definition, but will be called "Pierpont primes of the first kind" on this page to distinguish them. Task Write a routine (function, procedure, whatever) to find Pierpont primes of the first & second kinds. Use the routine to find and display here, on this page, the first 50 Pierpont primes of the first kind. Use the routine to find and display here, on this page, the first 50 Pierpont primes of the second kind If your language supports large integers, find and display here, on this page, the 250th Pierpont prime of the first kind and the 250th Pierpont prime of the second kind. See also Wikipedia - Pierpont primes OEIS:A005109 - Class 1 -, or Pierpont primes OEIS:A005105 - Class 1 +, or Pierpont primes of the second kind
#Phix
Phix
-- demo/rosetta/Pierpont_primes.exw with javascript_semantics include mpfr.e function pierpont(integer n) sequence p = {{mpz_init(2)},{}}, s = {mpz_init(1)} integer i2 = 1, i3 = 1 mpz {n2, n3, t} = mpz_inits(3) atom t1 = time()+1 while min(length(p[1]),length(p[2])) < n do mpz_mul_si(n2,s[i2],2) mpz_mul_si(n3,s[i3],3) if mpz_cmp(n2,n3)<0 then mpz_set(t,n2) i2 += 1 else mpz_set(t,n3) i3 += 1 end if if mpz_cmp(t,s[$]) > 0 then s = append(s, mpz_init_set(t)) mpz_add_ui(t,t,1) if length(p[1]) < n and mpz_prime(t) then p[1] = append(p[1],mpz_init_set(t)) end if mpz_sub_ui(t,t,2) if length(p[2]) < n and mpz_prime(t) then p[2] = append(p[2],mpz_init_set(t)) end if end if if time()>t1 then printf(1,"Found: 1st:%d/%d, 2nd:%d/%d\r", {length(p[1]),n,length(p[2]),n}) t1 = time()+1 end if end while return p end function --constant limit = 2000 -- 2 mins --constant limit = 1000 -- 8.1s constant limit = 250 -- 0.1s atom t0 = time() sequence p = pierpont(limit) constant fs = {"first","second"} for i=1 to length(fs) do printf(1,"First 50 Pierpont primes of the %s kind:\n",{fs[i]}) for j=1 to 50 do printf(1,"%8s ", {mpz_get_str(p[i][j])}) if mod(j,10)=0 then printf(1,"\n") end if end for printf(1,"\n") end for constant t = {250,1000,2000} for i=1 to length(t) do integer ti = t[i] if ti>limit then exit end if for j=1 to length(fs) do string zs = shorten(mpz_get_str(p[j][ti])) printf(1,"%dth Pierpont prime of the %s kind: %s\n",{ti,fs[j],zs}) end for printf(1,"\n") end for printf(1,"Took %s\n", elapsed(time()-t0))
http://rosettacode.org/wiki/Pick_random_element
Pick random element
Demonstrate how to pick a random element from a list.
#Fortran
Fortran
program pick_random implicit none   integer :: i integer :: a(10) = (/ (i, i = 1, 10) /) real :: r   call random_seed call random_number(r) write(*,*) a(int(r*size(a)) + 1) end program
http://rosettacode.org/wiki/Pick_random_element
Pick random element
Demonstrate how to pick a random element from a list.
#Free_Pascal
Free Pascal
' FB 1.05.0 Win64   Dim a(0 To 9) As String = {"Zero", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine"}   Randomize Dim randInt As Integer   For i As Integer = 1 To 5 randInt = Int(Rnd * 10) Print a(randInt) Next Sleep
http://rosettacode.org/wiki/Primality_by_trial_division
Primality by trial division
Task Write a boolean function that tells whether a given integer is prime. Remember that   1   and all non-positive numbers are not prime. Use trial division. Even numbers greater than   2   may be eliminated right away. A loop from   3   to   √ n    will suffice,   but other loops are allowed. Related tasks   count in factors   prime decomposition   AKS test for primes   factors of an integer   Sieve of Eratosthenes   factors of a Mersenne number   trial factoring of a Mersenne number   partition an integer X into N primes   sequence of primes by Trial Division
#V
V
[prime? 2 [[dup * >] [true] [false] ifte [% 0 >] dip and] [succ] while dup * <].
http://rosettacode.org/wiki/Phrase_reversals
Phrase reversals
Task Given a string of space separated words containing the following phrase: rosetta code phrase reversal Reverse the characters of the string. Reverse the characters of each individual word in the string, maintaining original word order within the string. Reverse the order of each word of the string, maintaining the order of characters in each word. Show your output here. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#FreeBASIC
FreeBASIC
' FB 1.05.0 Win64   Sub split (s As Const String, sepList As Const String, result() As String) If s = "" OrElse sepList = "" Then Redim result(0) result(0) = s Return End If Dim As Integer i, j, count = 0, empty = 0, length Dim As Integer position(Len(s) + 1) position(0) = 0   For i = 0 To len(s) - 1 For j = 0 to Len(sepList) - 1 If s[i] = sepList[j] Then count += 1 position(count) = i + 1 End If Next j Next i   Redim result(count) If count = 0 Then result(0) = s Return End If   position(count + 1) = len(s) + 1   For i = 1 To count + 1 length = position(i) - position(i - 1) - 1 result(i - 1) = Mid(s, position(i - 1) + 1, length) Next End Sub   Function reverse(s As Const String) As String If s = "" Then Return "" Dim t As String = s Dim length As Integer = Len(t) For i As Integer = 0 to length\2 - 1 Swap t[i], t[length - 1 - i] Next Return t End Function   Dim s As String = "rosetta code phrase reversal" Dim a() As String Dim sepList As String = " "   Print "Original string => "; s Print "Reversed string => "; reverse(s) Print "Reversed words => "; split s, sepList, a() For i As Integer = LBound(a) To UBound(a) Print reverse(a(i)); " "; Next Print Print "Reversed order => "; For i As Integer = UBound(a) To LBound(a) Step -1 Print a(i); " "; Next Print : Print Print "Press any key to quit" Sleep
http://rosettacode.org/wiki/Permutations/Derangements
Permutations/Derangements
A derangement is a permutation of the order of distinct items in which no item appears in its original place. For example, the only two derangements of the three items (0, 1, 2) are (1, 2, 0), and (2, 0, 1). The number of derangements of n distinct items is known as the subfactorial of n, sometimes written as !n. There are various ways to calculate !n. Task Create a named function/method/subroutine/... to generate derangements of the integers 0..n-1, (or 1..n if you prefer). Generate and show all the derangements of 4 integers using the above routine. Create a function that calculates the subfactorial of n, !n. Print and show a table of the counted number of derangements of n vs. the calculated !n for n from 0..9 inclusive. Optional stretch goal   Calculate    !20 Related tasks   Anagrams/Deranged anagrams   Best shuffle   Left_factorials Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#D
D
import std.stdio, std.algorithm, std.typecons, std.conv, std.range, std.traits;   T factorial(T)(in T n) pure nothrow @safe @nogc { Unqual!T result = 1; foreach (immutable i; 2 .. n + 1) result *= i; return result; }   T subfact(T)(in T n) pure nothrow @safe @nogc { if (0 <= n && n <= 2) return n != 1; return (n - 1) * (subfact(n - 1) + subfact(n - 2)); }   auto derangements(in size_t n, in bool countOnly=false) pure nothrow @safe { size_t[] seq = n.iota.array; auto ori = seq.idup; size_t[][] all; size_t cnt = n == 0;   foreach (immutable tot; 0 .. n.factorial - 1) { size_t j = n - 2; while (seq[j] > seq[j + 1]) j--; size_t k = n - 1; while (seq[j] > seq[k]) k--; seq[k].swap(seq[j]);   size_t r = n - 1; size_t s = j + 1; while (r > s) { seq[s].swap(seq[r]); r--; s++; }   j = 0; while (j < n && seq[j] != ori[j]) j++; if (j == n) { if (countOnly) cnt++; else all ~= seq.dup; } }   return tuple(all, cnt); }   void main() @safe { "Derangements for n = 4:".writeln; foreach (const d; 4.derangements[0]) d.writeln;   "\nTable of n vs counted vs calculated derangements:".writeln; foreach (immutable i; 0 .. 10) writefln("%s  %-7s%-7s", i, derangements(i, 1)[1], i.subfact);   writefln("\n!20 = %s", 20L.subfact); }
http://rosettacode.org/wiki/Permutations_by_swapping
Permutations by swapping
Task Generate permutations of n items in which successive permutations differ from each other by the swapping of any two items. Also generate the sign of the permutation which is +1 when the permutation is generated from an even number of swaps from the initial state, and -1 for odd. Show the permutations and signs of three items, in order of generation here. Such data are of use in generating the determinant of a square matrix and any functions created should bear this in mind. Note: The Steinhaus–Johnson–Trotter algorithm generates successive permutations where adjacent items are swapped, but from this discussion adjacency is not a requirement. References Steinhaus–Johnson–Trotter algorithm Johnson-Trotter Algorithm Listing All Permutations Heap's algorithm [1] Tintinnalogia Related tasks   Matrix arithmetic   Gray code
#EchoLisp
EchoLisp
  (lib 'list)   (for/fold (sign 1) ((σ (in-permutations 4)) (count 100)) (printf "perm: %a count:%4d sign:%4d" σ count sign) (* sign -1))   perm: (0 1 2 3) count: 0 sign: 1 perm: (0 1 3 2) count: 1 sign: -1 perm: (0 3 1 2) count: 2 sign: 1 perm: (3 0 1 2) count: 3 sign: -1 perm: (3 0 2 1) count: 4 sign: 1 perm: (0 3 2 1) count: 5 sign: -1 perm: (0 2 3 1) count: 6 sign: 1 perm: (0 2 1 3) count: 7 sign: -1 perm: (2 0 1 3) count: 8 sign: 1 perm: (2 0 3 1) count: 9 sign: -1 perm: (2 3 0 1) count: 10 sign: 1 perm: (3 2 0 1) count: 11 sign: -1 perm: (3 2 1 0) count: 12 sign: 1 perm: (2 3 1 0) count: 13 sign: -1 perm: (2 1 3 0) count: 14 sign: 1 perm: (2 1 0 3) count: 15 sign: -1 perm: (1 2 0 3) count: 16 sign: 1 perm: (1 2 3 0) count: 17 sign: -1 perm: (1 3 2 0) count: 18 sign: 1 perm: (3 1 2 0) count: 19 sign: -1 perm: (3 1 0 2) count: 20 sign: 1 perm: (1 3 0 2) count: 21 sign: -1 perm: (1 0 3 2) count: 22 sign: 1 perm: (1 0 2 3) count: 23 sign: -1  
http://rosettacode.org/wiki/Permutation_test
Permutation test
Permutation test You are encouraged to solve this task according to the task description, using any language you may know. A new medical treatment was tested on a population of n + m {\displaystyle n+m} volunteers, with each volunteer randomly assigned either to a group of n {\displaystyle n} treatment subjects, or to a group of m {\displaystyle m} control subjects. Members of the treatment group were given the treatment, and members of the control group were given a placebo. The effect of the treatment or placebo on each volunteer was measured and reported in this table. Table of experimental results Treatment group Control group 85 68 88 41 75 10 66 49 25 16 29 65 83 32 39 92 97 28 98 Write a program that performs a permutation test to judge whether the treatment had a significantly stronger effect than the placebo. Do this by considering every possible alternative assignment from the same pool of volunteers to a treatment group of size n {\displaystyle n} and a control group of size m {\displaystyle m} (i.e., the same group sizes used in the actual experiment but with the group members chosen differently), while assuming that each volunteer's effect remains constant regardless. Note that the number of alternatives will be the binomial coefficient ( n + m n ) {\displaystyle {\tbinom {n+m}{n}}} . Compute the mean effect for each group and the difference in means between the groups in every case by subtracting the mean of the control group from the mean of the treatment group. Report the percentage of alternative groupings for which the difference in means is less or equal to the actual experimentally observed difference in means, and the percentage for which it is greater. Note that they should sum to 100%. Extremely dissimilar values are evidence of an effect not entirely due to chance, but your program need not draw any conclusions. You may assume the experimental data are known at compile time if that's easier than loading them at run time. Test your solution on the data given above.
#Go
Go
package main   import "fmt"   var tr = []int{85, 88, 75, 66, 25, 29, 83, 39, 97} var ct = []int{68, 41, 10, 49, 16, 65, 32, 92, 28, 98}   func main() { // collect all results in a single list all := make([]int, len(tr)+len(ct)) copy(all, tr) copy(all[len(tr):], ct)   // compute sum of all data, useful as intermediate result var sumAll int for _, r := range all { sumAll += r }   // closure for computing scaled difference. // compute results scaled by len(tr)*len(ct). // this allows all math to be done in integers. sd := func(trc []int) int { var sumTr int for _, x := range trc { sumTr += all[x] } return sumTr*len(ct) - (sumAll-sumTr)*len(tr) }   // compute observed difference, as an intermediate result a := make([]int, len(tr)) for i, _ := range a { a[i] = i } sdObs := sd(a)   // iterate over all combinations. for each, compute (scaled) // difference and tally whether leq or gt observed difference. var nLe, nGt int comb(len(all), len(tr), func(c []int) { if sd(c) > sdObs { nGt++ } else { nLe++ } })   // print results as percentage pc := 100 / float64(nLe+nGt) fmt.Printf("differences <= observed: %f%%\n", float64(nLe)*pc) fmt.Printf("differences > observed: %f%%\n", float64(nGt)*pc) }   // combination generator, copied from combination task func comb(n, m int, emit func([]int)) { s := make([]int, m) last := m - 1 var rc func(int, int) rc = func(i, next int) { for j := next; j < n; j++ { s[i] = j if i == last { emit(s) } else { rc(i+1, j+1) } } return } rc(0, 0) }
http://rosettacode.org/wiki/Percolation/Mean_cluster_density
Percolation/Mean cluster density
Percolation Simulation This is a simulation of aspects of mathematical percolation theory. For other percolation simulations, see Category:Percolation Simulations, or: 1D finite grid simulation Mean run density 2D finite grid simulations Site percolation | Bond percolation | Mean cluster density Let c {\displaystyle c} be a 2D boolean square matrix of n × n {\displaystyle n\times n} values of either 1 or 0 where the probability of any value being 1 is p {\displaystyle p} , (and of 0 is therefore 1 − p {\displaystyle 1-p} ). We define a cluster of 1's as being a group of 1's connected vertically or horizontally (i.e., using the Von Neumann neighborhood rule) and bounded by either 0 {\displaystyle 0} or by the limits of the matrix. Let the number of such clusters in such a randomly constructed matrix be C n {\displaystyle C_{n}} . Percolation theory states that K ( p ) {\displaystyle K(p)} (the mean cluster density) will satisfy K ( p ) = C n / n 2 {\displaystyle K(p)=C_{n}/n^{2}} as n {\displaystyle n} tends to infinity. For p = 0.5 {\displaystyle p=0.5} , K ( p ) {\displaystyle K(p)} is found numerically to approximate 0.065770 {\displaystyle 0.065770} ... Task Show the effect of varying n {\displaystyle n} on the accuracy of simulated K ( p ) {\displaystyle K(p)} for p = 0.5 {\displaystyle p=0.5} and for values of n {\displaystyle n} up to at least 1000 {\displaystyle 1000} . Any calculation of C n {\displaystyle C_{n}} for finite n {\displaystyle n} is subject to randomness, so an approximation should be computed as the average of t {\displaystyle t} runs, where t {\displaystyle t} ≥ 5 {\displaystyle 5} . For extra credit, graphically show clusters in a 15 × 15 {\displaystyle 15\times 15} , p = 0.5 {\displaystyle p=0.5} grid. Show your output here. See also s-Cluster on Wolfram mathworld.
#11l
11l
UInt32 seed = 0 F nonrandom()  :seed = 1664525 * :seed + 1013904223 R (:seed >> 16) / Float(FF'FF)   V nn = 15 V tt = 5 V pp = 0.5 V NotClustered = 1 V Cell2Char = ‘ #abcdefghijklmnopqrstuvwxyz’ V NRange = [4, 64, 256, 1024, 4096]   F newGrid(n, p) R (0 .< n).map(i -> (0 .< @n).map(i -> Int(nonrandom() < @@p)))   F walkMaze(&grid, m, n, idx) -> N grid[n][m] = idx I n < grid.len - 1 & grid[n + 1][m] == NotClustered walkMaze(&grid, m, n + 1, idx) I m < grid[0].len - 1 & grid[n][m + 1] == NotClustered walkMaze(&grid, m + 1, n, idx) I m > 0 & grid[n][m - 1] == NotClustered walkMaze(&grid, m - 1, n, idx) I n > 0 & grid[n - 1][m] == NotClustered walkMaze(&grid, m, n - 1, idx)   F clusterCount(&grid) V walkIndex = 1 L(n) 0 .< grid.len L(m) 0 .< grid[0].len I grid[n][m] == NotClustered walkIndex++ walkMaze(&grid, m, n, walkIndex) R walkIndex - 1   F clusterDensity(n, p) V grid = newGrid(n, p) R clusterCount(&grid) / Float(n * n)   F print_grid(grid) L(row) grid print(L.index % 10, end' ‘) ’) L(cell) row print(‘ ’Cell2Char[cell], end' ‘’) print()   V grid = newGrid(nn, 0.5) print(‘Found ’clusterCount(&grid)‘ clusters in this ’nn‘ by ’nn" grid\n") print_grid(grid) print()   L(n) NRange V sum = 0.0 L 0 .< tt sum += clusterDensity(n, pp) V sim = sum / tt print(‘t = #. p = #.2 n = #4 sim = #.5’.format(tt, pp, n, sim))
http://rosettacode.org/wiki/Percolation/Mean_run_density
Percolation/Mean run density
Percolation Simulation This is a simulation of aspects of mathematical percolation theory. For other percolation simulations, see Category:Percolation Simulations, or: 1D finite grid simulation Mean run density 2D finite grid simulations Site percolation | Bond percolation | Mean cluster density Let v {\displaystyle v} be a vector of n {\displaystyle n} values of either 1 or 0 where the probability of any value being 1 is p {\displaystyle p} ; the probability of a value being 0 is therefore 1 − p {\displaystyle 1-p} . Define a run of 1s as being a group of consecutive 1s in the vector bounded either by the limits of the vector or by a 0. Let the number of such runs in a given vector of length n {\displaystyle n} be R n {\displaystyle R_{n}} . For example, the following vector has R 10 = 3 {\displaystyle R_{10}=3} [1 1 0 0 0 1 0 1 1 1] ^^^ ^ ^^^^^ Percolation theory states that K ( p ) = lim n → ∞ R n / n = p ( 1 − p ) {\displaystyle K(p)=\lim _{n\to \infty }R_{n}/n=p(1-p)} Task Any calculation of R n / n {\displaystyle R_{n}/n} for finite n {\displaystyle n} is subject to randomness so should be computed as the average of t {\displaystyle t} runs, where t ≥ 100 {\displaystyle t\geq 100} . For values of p {\displaystyle p} of 0.1, 0.3, 0.5, 0.7, and 0.9, show the effect of varying n {\displaystyle n} on the accuracy of simulated K ( p ) {\displaystyle K(p)} . Show your output here. See also s-Run on Wolfram mathworld.
#C.2B.2B
C++
#include <algorithm> #include <random> #include <vector> #include <iostream> #include <numeric> #include <iomanip> using VecIt = std::vector<int>::const_iterator ;   //creates vector of length n, based on probability p for 1 std::vector<int> createVector( int n, double p ) { std::vector<int> result( n ) ; std::random_device rd ; std::mt19937 gen( rd( ) ) ; std::uniform_real_distribution<> dis( 0 , 1 ) ; for ( int i = 0 ; i < n ; i++ ) { double number = dis( gen ) ; if ( number <= p ) result[ i ] = 1 ; else result[ i ] = 0 ; } return result ; }   //find number of 1 runs in the vector int find_Runs( const std::vector<int> & numberVector ) { int runs = 0 ; VecIt found = numberVector.begin( ) ; while ( ( found = std::find( found , numberVector.end( ) , 1 ) ) != numberVector.end( ) ) { runs++ ; while ( found != numberVector.end( ) && ( *found == 1 ) ) std::advance( found , 1 ) ; if ( found == numberVector.end( ) ) break ; } return runs ; }   int main( ) { std::cout << "t = 100\n" ; std::vector<double> p_values { 0.1 , 0.3 , 0.5 , 0.7 , 0.9 } ; for ( double p : p_values ) { std::cout << "p = " << p << " , K(p) = " << p * ( 1 - p ) << std::endl ; for ( int n = 10 ; n < 100000 ; n *= 10 ) { std::vector<double> runsFound ; for ( int i = 0 ; i < 100 ; i++ ) { std::vector<int> ones_and_zeroes = createVector( n , p ) ; runsFound.push_back( find_Runs( ones_and_zeroes ) / static_cast<double>( n ) ) ; } double average = std::accumulate( runsFound.begin( ) , runsFound.end( ) , 0.0 ) / runsFound.size( ) ; std::cout << " R(" << std::setw( 6 ) << std::right << n << ", p) = " << average << std::endl ; } } return 0 ; }
http://rosettacode.org/wiki/Percolation/Site_percolation
Percolation/Site percolation
Percolation Simulation This is a simulation of aspects of mathematical percolation theory. For other percolation simulations, see Category:Percolation Simulations, or: 1D finite grid simulation Mean run density 2D finite grid simulations Site percolation | Bond percolation | Mean cluster density Given an M × N {\displaystyle M\times N} rectangular array of cells numbered c e l l [ 0.. M − 1 , 0.. N − 1 ] {\displaystyle \mathrm {cell} [0..M-1,0..N-1]} assume M {\displaystyle M} is horizontal and N {\displaystyle N} is downwards. Assume that the probability of any cell being filled is a constant p {\displaystyle p} where 0.0 ≤ p ≤ 1.0 {\displaystyle 0.0\leq p\leq 1.0} The task Simulate creating the array of cells with probability p {\displaystyle p} and then testing if there is a route through adjacent filled cells from any on row 0 {\displaystyle 0} to any on row N {\displaystyle N} , i.e. testing for site percolation. Given p {\displaystyle p} repeat the percolation t {\displaystyle t} times to estimate the proportion of times that the fluid can percolate to the bottom for any given p {\displaystyle p} . Show how the probability of percolating through the random grid changes with p {\displaystyle p} going from 0.0 {\displaystyle 0.0} to 1.0 {\displaystyle 1.0} in 0.1 {\displaystyle 0.1} increments and with the number of repetitions to estimate the fraction at any given p {\displaystyle p} as t >= 100 {\displaystyle t>=100} . Use an M = 15 , N = 15 {\displaystyle M=15,N=15} grid of cells for all cases. Optionally depict a percolation through a cell grid graphically. Show all output on this page.
#D
D
import std.stdio, std.random, std.array, std.datetime;   enum size_t nCols = 15, nRows = 15, nSteps = 11, // Probability granularity. nTries = 20_000; // Simulation tries.   enum Cell : char { empty = ' ', filled = '#', visited = '.' } alias Grid = Cell[nCols][nRows];   void initialize(ref Grid grid, in double probability, ref Xorshift rng) { foreach (ref row; grid) foreach (ref cell; row) cell = (rng.uniform01 < probability) ? Cell.empty : Cell.filled; }   void show(in ref Grid grid) @safe { writefln("%(|%(%c%)|\n%)|", grid); }   bool percolate(ref Grid grid) pure nothrow @safe @nogc { bool walk(in size_t r, in size_t c) nothrow @safe @nogc { enum bottom = nRows - 1; grid[r][c] = Cell.visited;   if (r < bottom && grid[r + 1][c] == Cell.empty) { // Down. if (walk(r + 1, c)) return true; } else if (r == bottom) return true;   if (c && grid[r][c - 1] == Cell.empty) // Left. if (walk(r, c - 1)) return true;   if (c < nCols - 1 && grid[r][c + 1] == Cell.empty) // Right. if (walk(r, c + 1)) return true;   if (r && grid[r - 1][c] == Cell.empty) // Up. if (walk(r - 1, c)) return true;   return false; }   enum startR = 0; foreach (immutable c; 0 .. nCols) if (grid[startR][c] == Cell.empty) if (walk(startR, c)) return true; return false; }   void main() { static struct Counter { double prob; size_t count; }   StopWatch sw; sw.start;   enum probabilityStep = 1.0 / (nSteps - 1); Counter[nSteps] counters; foreach (immutable i, ref co; counters) co.prob = i * probabilityStep;   Grid grid; bool sampleShown = false; auto rng = Xorshift(unpredictableSeed);   foreach (ref co; counters) { foreach (immutable _; 0 .. nTries) { grid.initialize(co.prob, rng); if (grid.percolate) { co.count++; if (!sampleShown) { writefln("Percolating sample (%dx%d, probability =%5.2f):", nCols, nRows, co.prob); grid.show; sampleShown = true; } } } } sw.stop;   writefln("\nFraction of %d tries that percolate through:", nTries); foreach (const co; counters) writefln("%1.3f %1.3f", co.prob, co.count / double(nTries));   writefln("\nSimulations and grid printing performed" ~ " in %3.2f seconds.", sw.peek.msecs / 1000.0); }
http://rosettacode.org/wiki/Permutations
Permutations
Task Write a program that generates all   permutations   of   n   different objects.   (Practically numerals!) Related tasks   Find the missing permutation   Permutations/Derangements The number of samples of size k from n objects. With   combinations and permutations   generation tasks. Order Unimportant Order Important Without replacement ( n k ) = n C k = n ( n − 1 ) … ( n − k + 1 ) k ( k − 1 ) … 1 {\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}} n P k = n ⋅ ( n − 1 ) ⋅ ( n − 2 ) ⋯ ( n − k + 1 ) {\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)} Task: Combinations Task: Permutations With replacement ( n + k − 1 k ) = n + k − 1 C k = ( n + k − 1 ) ! ( n − 1 ) ! k ! {\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}} n k {\displaystyle n^{k}} Task: Combinations with repetitions Task: Permutations with repetitions
#360_Assembly
360 Assembly
* Permutations 26/10/2015 PERMUTE CSECT USING PERMUTE,R15 set base register LA R9,TMP-A n=hbound(a) SR R10,R10 nn=0 LOOP LA R10,1(R10) nn=nn+1 LA R11,PG pgi=@pg LA R6,1 i=1 LOOPI1 CR R6,R9 do i=1 to n BH ELOOPI1 LA R2,A-1(R6) @a(i) MVC 0(1,R11),0(R2) output a(i) LA R11,1(R11) pgi=pgi+1 LA R6,1(R6) i=i+1 B LOOPI1 ELOOPI1 XPRNT PG,80 LR R6,R9 i=n LOOPUIM BCTR R6,0 i=i-1 LTR R6,R6 until i=0 BE ELOOPUIM LA R2,A-1(R6) @a(i) LA R3,A(R6) @a(i+1) CLC 0(1,R2),0(R3) or until a(i)<a(i+1) BNL LOOPUIM ELOOPUIM LR R7,R6 j=i LA R7,1(R7) j=i+1 LR R8,R9 k=n LOOPWJ CR R7,R8 do while j<k BNL ELOOPWJ LA R2,A-1(R7) r2=@a(j) LA R3,A-1(R8) r3=@a(k) MVC TMP,0(R2) tmp=a(j) MVC 0(1,R2),0(R3) a(j)=a(k) MVC 0(1,R3),TMP a(k)=tmp LA R7,1(R7) j=j+1 BCTR R8,0 k=k-1 B LOOPWJ ELOOPWJ LTR R6,R6 if i>0 BNP ILE0 LR R7,R6 j=i LA R7,1(R7) j=i+1 LOOPWA LA R2,A-1(R7) @a(j) LA R3,A-1(R6) @a(i) CLC 0(1,R2),0(R3) do while a(j)<a(i) BNL AJGEAI LA R7,1(R7) j=j+1 B LOOPWA AJGEAI LA R2,A-1(R7) r2=@a(j) LA R3,A-1(R6) r3=@a(i) MVC TMP,0(R2) tmp=a(j) MVC 0(1,R2),0(R3) a(j)=a(i) MVC 0(1,R3),TMP a(i)=tmp ILE0 LTR R6,R6 until i<>0 BNE LOOP XR R15,R15 set return code BR R14 return to caller A DC C'ABCD' <== input TMP DS C temp for swap PG DC CL80' ' buffer YREGS END PERMUTE
http://rosettacode.org/wiki/Perfect_shuffle
Perfect shuffle
A perfect shuffle (or faro/weave shuffle) means splitting a deck of cards into equal halves, and perfectly interleaving them - so that you end up with the first card from the left half, followed by the first card from the right half, and so on: 7♠ 8♠ 9♠ J♠ Q♠ K♠→7♠  8♠  9♠   J♠  Q♠  K♠→7♠ J♠ 8♠ Q♠ 9♠ K♠ When you repeatedly perform perfect shuffles on an even-sized deck of unique cards, it will at some point arrive back at its original order. How many shuffles this takes, depends solely on the number of cards in the deck - for example for a deck of eight cards it takes three shuffles: original: 1 2 3 4 5 6 7 8 after 1st shuffle: 1 5 2 6 3 7 4 8 after 2nd shuffle: 1 3 5 7 2 4 6 8 after 3rd shuffle: 1 2 3 4 5 6 7 8 The Task Write a function that can perform a perfect shuffle on an even-sized list of values. Call this function repeatedly to count how many shuffles are needed to get a deck back to its original order, for each of the deck sizes listed under "Test Cases" below. You can use a list of numbers (or anything else that's convenient) to represent a deck; just make sure that all "cards" are unique within each deck. Print out the resulting shuffle counts, to demonstrate that your program passes the test-cases. Test Cases input (deck size) output (number of shuffles required) 8 3 24 11 52 8 100 30 1020 1018 1024 10 10000 300
#Action.21
Action!
DEFINE MAXDECK="5000"   PROC Order(INT ARRAY deck INT count) INT i   FOR i=0 TO count-1 DO deck(i)=i OD RETURN   BYTE FUNC IsOrdered(INT ARRAY deck INT count) INT i   FOR i=0 TO count-1 DO IF deck(i)#i THEN RETURN (0) FI OD RETURN (1)   PROC Shuffle(INT ARRAY src,dst INT count) INT i,i1,i2   i=0 i1=0 i2=count RSH 1 WHILE i<count DO dst(i)=src(i1) i==+1 i1==+1 dst(i)=src(i2) i==+1 i2==+1 OD RETURN   PROC Test(INT ARRAY deck,deck2 INT count) INT ARRAY tmp INT n   Order(deck,count) n=0 DO Shuffle(deck,deck2,count) tmp=deck deck=deck2 deck2=tmp n==+1 Poke(77,0) ;turn off the attract mode PrintF("%I cards -> %I iterations%E",count,n) Put(28) ;move cursor up UNTIL IsOrdered(deck,count) OD PutE() RETURN   PROC Main() INT ARRAY deck(MAXDECK),deck2(MAXDECK) INT ARRAY counts=[8 24 52 100 1020 1024 MAXDECK] INT i   FOR i=0 TO 6 DO Test(deck,deck2,counts(i)) OD RETURN
http://rosettacode.org/wiki/Perfect_shuffle
Perfect shuffle
A perfect shuffle (or faro/weave shuffle) means splitting a deck of cards into equal halves, and perfectly interleaving them - so that you end up with the first card from the left half, followed by the first card from the right half, and so on: 7♠ 8♠ 9♠ J♠ Q♠ K♠→7♠  8♠  9♠   J♠  Q♠  K♠→7♠ J♠ 8♠ Q♠ 9♠ K♠ When you repeatedly perform perfect shuffles on an even-sized deck of unique cards, it will at some point arrive back at its original order. How many shuffles this takes, depends solely on the number of cards in the deck - for example for a deck of eight cards it takes three shuffles: original: 1 2 3 4 5 6 7 8 after 1st shuffle: 1 5 2 6 3 7 4 8 after 2nd shuffle: 1 3 5 7 2 4 6 8 after 3rd shuffle: 1 2 3 4 5 6 7 8 The Task Write a function that can perform a perfect shuffle on an even-sized list of values. Call this function repeatedly to count how many shuffles are needed to get a deck back to its original order, for each of the deck sizes listed under "Test Cases" below. You can use a list of numbers (or anything else that's convenient) to represent a deck; just make sure that all "cards" are unique within each deck. Print out the resulting shuffle counts, to demonstrate that your program passes the test-cases. Test Cases input (deck size) output (number of shuffles required) 8 3 24 11 52 8 100 30 1020 1018 1024 10 10000 300
#Ada
Ada
with ada.text_io;use ada.text_io;   procedure perfect_shuffle is function count_shuffle (half_size : Positive) return Positive is subtype index is Natural range 0..2 * half_size - 1; subtype index_that_move is index range index'first+1..index'last-1; type deck is array (index) of index; initial, d, next : deck; count : Natural := 1; begin for i in index loop initial (i) := i; end loop; d := initial; loop for i in index_that_move loop next (i) := (if d (i) mod 2 = 0 then d(i)/2 else d(i)/2 + half_size); end loop; exit when next (index_that_move)= initial(index_that_move); d := next; count := count + 1; end loop; return count; end count_shuffle; test : array (Positive range <>) of Positive := (8, 24, 52, 100, 1020, 1024, 10_000); begin for size of test loop put_line ("For" & size'img & " cards, there are "& count_shuffle (size / 2)'img & " shuffles needed."); end loop; end perfect_shuffle;
http://rosettacode.org/wiki/Perlin_noise
Perlin noise
The   Perlin noise   is a kind of   gradient noise   invented by   Ken Perlin   around the end of the twentieth century and still currently heavily used in   computer graphics,   most notably to procedurally generate textures or heightmaps. The Perlin noise is basically a   pseudo-random   mapping of   R d {\displaystyle \mathbb {R} ^{d}}   into   R {\displaystyle \mathbb {R} }   with an integer   d {\displaystyle d}   which can be arbitrarily large but which is usually   2,   3,   or   4. Either by using a dedicated library or by implementing the algorithm, show that the Perlin noise   (as defined in 2002 in the Java implementation below)   of the point in 3D-space with coordinates     3.14,   42,   7     is     0.13691995878400012. Note: this result assumes 64 bit IEEE-754 floating point calculations. If your language uses a different floating point representation, make a note of it and calculate the value accurate to 15 decimal places, or your languages accuracy threshold if it is less. Trailing zeros need not be displayed.
#Delphi
Delphi
x floor >integer 255 bitand :> X y floor >integer 255 bitand :> Y z floor >integer 255 bitand :> Z
http://rosettacode.org/wiki/Perfect_totient_numbers
Perfect totient numbers
Generate and show here, the first twenty Perfect totient numbers. Related task   Totient function Also see   the OEIS entry for   perfect totient numbers.   mrob   list of the first 54
#BASIC256
BASIC256
found = 0 curr = 3   while found < 20 sum = Totient(curr) toti = sum while toti <> 1 toti = Totient(toti) sum += toti end while if sum = curr then print sum found += 1 end if curr += 1 end while end   function GCD(n, d) if n = 0 then return d if d = 0 then return n if n > d then return GCD(d, (n mod d)) return GCD(n, (d mod n)) end function   function Totient(n) phi = 0 for m = 1 to n if GCD(m, n) = 1 then phi += 1 next m return phi end function
http://rosettacode.org/wiki/Perfect_totient_numbers
Perfect totient numbers
Generate and show here, the first twenty Perfect totient numbers. Related task   Totient function Also see   the OEIS entry for   perfect totient numbers.   mrob   list of the first 54
#BCPL
BCPL
get "libhdr"   let gcd(a,b) = b=0 -> a, gcd(b, a rem b)   let totient(n) = valof $( let r = 0 for i=1 to n-1 if gcd(n,i) = 1 then r := r + 1 resultis r $)   let perfect(n) = valof $( let sum = 0 and x = n $( x := totient(x) sum := sum + x $) repeatuntil x = 1 resultis sum = n $)   let start() be $( let seen = 0 and n = 3 while seen < 20 $( if perfect(n) $( writef("%N ", n) seen := seen + 1 $) n := n + 2 $) wrch('*N') $)
http://rosettacode.org/wiki/Playing_cards
Playing cards
Task Create a data structure and the associated methods to define and manipulate a deck of   playing cards. The deck should contain 52 unique cards. The methods must include the ability to:   make a new deck   shuffle (randomize) the deck   deal from the deck   print the current contents of a deck Each card must have a pip value and a suit value which constitute the unique value of the card. Related tasks: Card shuffles Deal cards_for_FreeCell War Card_Game Poker hand_analyser Go Fish
#Delphi
Delphi
program Cards;   {$APPTYPE CONSOLE}   uses SysUtils, Classes;   type TPip = (pTwo, pThree, pFour, pFive, pSix, pSeven, pEight, pNine, pTen, pJack, pQueen, pKing, pAce); TSuite = (sDiamonds, sSpades, sHearts, sClubs);   const cPipNames: array[TPip] of string = ('2', '3', '4', '5', '6', '7', '8', '9', '10', 'J', 'Q', 'K', 'A'); cSuiteNames: array[TSuite] of string = ('Diamonds', 'Spades', 'Hearts', 'Clubs');   type TCard = class private FSuite: TSuite; FPip: TPip; public constructor Create(aSuite: TSuite; aPip: TPip); function ToString: string; override;   property Pip: TPip read FPip; property Suite: TSuite read FSuite; end;   TDeck = class private FCards: TList; public constructor Create; destructor Destroy; override; procedure Shuffle; function Deal: TCard; function ToString: string; override; end;   { TCard }   constructor TCard.Create(aSuite: TSuite; aPip: TPip); begin FSuite := aSuite; FPip := aPip; end;   function TCard.ToString: string; begin Result := Format('%s of %s', [cPipNames[Pip], cSuiteNames[Suite]]) end;   { TDeck }   constructor TDeck.Create; var pip: TPip; suite: TSuite; begin FCards := TList.Create; for suite := Low(TSuite) to High(TSuite) do for pip := Low(TPip) to High(TPip) do FCards.Add(TCard.Create(suite, pip)); end;   function TDeck.Deal: TCard; begin Result := FCards[0]; FCards.Delete(0); end;   destructor TDeck.Destroy; var i: Integer; c: TCard; begin for i := FCards.Count - 1 downto 0 do begin c := FCards[i]; FCards.Delete(i); c.Free; end; FCards.Free; inherited; end;   procedure TDeck.Shuffle; var i, j: Integer; temp: TCard; begin Randomize; for i := FCards.Count - 1 downto 0 do begin j := Random(FCards.Count); temp := FCards[j]; FCards.Delete(j); FCards.Add(temp); end; end;   function TDeck.ToString: string; var i: Integer; begin for i := 0 to FCards.Count - 1 do Writeln(TCard(FCards[i]).ToString); end;   begin with TDeck.Create do try Shuffle; ToString; Writeln; with Deal do try Writeln(ToString); finally Free; end; finally Free; end;   Readln; end.
http://rosettacode.org/wiki/Pi
Pi
Create a program to continually calculate and output the next decimal digit of   π {\displaystyle \pi }   (pi). The program should continue forever (until it is aborted by the user) calculating and outputting each decimal digit in succession. The output should be a decimal sequence beginning   3.14159265 ... Note: this task is about   calculating   pi.   For information on built-in pi constants see Real constants and functions. Related Task Arithmetic-geometric mean/Calculate Pi
#Crystal
Crystal
require "big"   def pi q, r, t, k, n, l = [1, 0, 1, 1, 3, 3].map { |n| BigInt.new(n) } dot_written = false loop do if 4*q + r - t < n*t yield n unless dot_written yield '.' dot_written = true end nr = 10*(r - n*t) n = ((10*(3*q + r)) / t) - 10*n q *= 10 r = nr else nr = (2*q + r) * l nn = (q*(7*k + 2) + r*l) / (t*l) q *= k t *= l l += 2 k += 1 n = nn r = nr end end end   pi { |digit_or_dot| print digit_or_dot; STDOUT.flush }  
http://rosettacode.org/wiki/Periodic_table
Periodic table
Task Display the row and column in the periodic table of the given atomic number. The periodic table Let us consider the following periodic table representation. __________________________________________________________________________ | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | | | |1 H He | | | |2 Li Be B C N O F Ne | | | |3 Na Mg Al Si P S Cl Ar | | | |4 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr | | | |5 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe | | | |6 Cs Ba * Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn | | | |7 Fr Ra ° Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og | |__________________________________________________________________________| | | | | |8 Lantanoidi* La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu | | | |9 Aktinoidi° Ak Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr | |__________________________________________________________________________| Example test cases;   1 -> 1 1   2 -> 1 18   29 -> 4 11   42 -> 5 6   57 -> 8 4   58 -> 8 5   72 -> 6 4   89 -> 9 4 Details; The representation of the periodic table may be represented in various way. The one presented in this challenge does have the following property : Lantanides and Aktinoides are all in a dedicated row, hence there is no element that is placed at 6, 3 nor 7, 3. You may take a look at the atomic number repartitions here. The atomic number is at least 1, at most 118. See also   the periodic table   This task was an idea from CompSciFact   The periodic table in ascii that was used as template
#Phix
Phix
with javascript_semantics constant match_wp = false function prc(integer n) constant t = {0,2,10,18,36,54,86,118,119} integer row = abs(binary_search(n,t,true))-1, col = n-t[row] if col>1+(row>1) then col = 18-(t[row+1]-n) if match_wp then if col<=2 then return {row+2,col+14} end if else -- matches above ascii: if col<=2+(row>5) then return {row+2,col+15} end if end if end if return {row,col} end function sequence pt = repeat(repeat(" ",19),10) pt[1][2..$] = apply(true,sprintf,{{"%3d"},tagset(18)}) -- column headings for i=1 to 9 do pt[i+1][1] = sprintf("%3d",i) end for -- row numbers for i=1 to 118 do integer {r,c} = prc(i) pt[r+1][c+1] = sprintf("%3d",i) end for if not match_wp then -- (ascii only:) pt[7][4] = " L*" pt[8][4] = " A*" pt[9][2..4] = {"Lanthanide:"} pt[10][2..4] = {" Actinide:"} end if printf(1,"%s\n",{join(apply(true,join,{pt,{"|"}}),"\n")})
http://rosettacode.org/wiki/Pig_the_dice_game
Pig the dice game
The   game of Pig   is a multiplayer game played with a single six-sided die.   The object of the game is to reach   100   points or more.   Play is taken in turns.   On each person's turn that person has the option of either: Rolling the dice:   where a roll of two to six is added to their score for that turn and the player's turn continues as the player is given the same choice again;   or a roll of   1   loses the player's total points   for that turn   and their turn finishes with play passing to the next player. Holding:   the player's score for that round is added to their total and becomes safe from the effects of throwing a   1   (one).   The player's turn finishes with play passing to the next player. Task Create a program to score for, and simulate dice throws for, a two-person game. Related task   Pig the dice game/Player
#JavaScript
JavaScript
let players = [ { name: '', score: 0 }, { name: '', score: 0 } ]; let curPlayer = 1, gameOver = false;   players[0].name = prompt('Your name, player #1:').toUpperCase(); players[1].name = prompt('Your name, player #2:').toUpperCase();   function roll() { return 1 + Math.floor(Math.random()*6) }   function round(player) { let curSum = 0, quit = false, dice; alert(`It's ${player.name}'s turn (${player.score}).`); while (!quit) { dice = roll(); if (dice == 1) { alert('You roll a 1. What a pity!'); quit = true; } else { curSum += dice; quit = !confirm(` You roll a ${dice} (sum: ${curSum}).\n Roll again? `); if (quit) { player.score += curSum; if (player.score >= 100) gameOver = true; } } } } // main while (!gameOver) { if (curPlayer == 0) curPlayer = 1; else curPlayer = 0; round(players[curPlayer]); if (gameOver) alert(` ${players[curPlayer].name} wins (${players[curPlayer].score}). `); }  
http://rosettacode.org/wiki/Pernicious_numbers
Pernicious numbers
A   pernicious number   is a positive integer whose   population count   is a prime. The   population count   is the number of   ones   in the binary representation of a non-negative integer. Example 22   (which is   10110   in binary)   has a population count of   3,   which is prime,   and therefore 22   is a pernicious number. Task display the first   25   pernicious numbers   (in decimal). display all pernicious numbers between   888,888,877   and   888,888,888   (inclusive). display each list of integers on one line   (which may or may not include a title). See also Sequence   A052294 pernicious numbers on The On-Line Encyclopedia of Integer Sequences. Rosetta Code entry   population count, evil numbers, odious numbers.
#EchoLisp
EchoLisp
  (lib 'sequences)   (define (pernicious? n) (prime? (bit-count n)))   (define pernicious (filter pernicious? [1 .. ])) (take pernicious 25) → (3 5 6 7 9 10 11 12 13 14 17 18 19 20 21 22 24 25 26 28 31 33 34 35 36)   (take (filter pernicious? [888888877 .. 888888889]) #:all) → (888888877 888888878 888888880 888888883 888888885 888888886)  
http://rosettacode.org/wiki/Permutations/Rank_of_a_permutation
Permutations/Rank of a permutation
A particular ranking of a permutation associates an integer with a particular ordering of all the permutations of a set of distinct items. For our purposes the ranking will assign integers 0.. ( n ! − 1 ) {\displaystyle 0..(n!-1)} to an ordering of all the permutations of the integers 0.. ( n − 1 ) {\displaystyle 0..(n-1)} . For example, the permutations of the digits zero to 3 arranged lexicographically have the following rank: PERMUTATION RANK (0, 1, 2, 3) -> 0 (0, 1, 3, 2) -> 1 (0, 2, 1, 3) -> 2 (0, 2, 3, 1) -> 3 (0, 3, 1, 2) -> 4 (0, 3, 2, 1) -> 5 (1, 0, 2, 3) -> 6 (1, 0, 3, 2) -> 7 (1, 2, 0, 3) -> 8 (1, 2, 3, 0) -> 9 (1, 3, 0, 2) -> 10 (1, 3, 2, 0) -> 11 (2, 0, 1, 3) -> 12 (2, 0, 3, 1) -> 13 (2, 1, 0, 3) -> 14 (2, 1, 3, 0) -> 15 (2, 3, 0, 1) -> 16 (2, 3, 1, 0) -> 17 (3, 0, 1, 2) -> 18 (3, 0, 2, 1) -> 19 (3, 1, 0, 2) -> 20 (3, 1, 2, 0) -> 21 (3, 2, 0, 1) -> 22 (3, 2, 1, 0) -> 23 Algorithms exist that can generate a rank from a permutation for some particular ordering of permutations, and that can generate the same rank from the given individual permutation (i.e. given a rank of 17 produce (2, 3, 1, 0) in the example above). One use of such algorithms could be in generating a small, random, sample of permutations of n {\displaystyle n} items without duplicates when the total number of permutations is large. Remember that the total number of permutations of n {\displaystyle n} items is given by n ! {\displaystyle n!} which grows large very quickly: A 32 bit integer can only hold 12 ! {\displaystyle 12!} , a 64 bit integer only 20 ! {\displaystyle 20!} . It becomes difficult to take the straight-forward approach of generating all permutations then taking a random sample of them. A question on the Stack Overflow site asked how to generate one million random and indivudual permutations of 144 items. Task Create a function to generate a permutation from a rank. Create the inverse function that given the permutation generates its rank. Show that for n = 3 {\displaystyle n=3} the two functions are indeed inverses of each other. Compute and show here 4 random, individual, samples of permutations of 12 objects. Stretch goal State how reasonable it would be to use your program to address the limits of the Stack Overflow question. References Ranking and Unranking Permutations in Linear Time by Myrvold & Ruskey. (Also available via Google here). Ranks on the DevData site. Another answer on Stack Overflow to a different question that explains its algorithm in detail. Related tasks Factorial_base_numbers_indexing_permutations_of_a_collection
#Scala
Scala
import scala.math._   def factorial(n: Int): BigInt = { (1 to n).map(BigInt.apply).fold(BigInt(1))(_ * _) }   def indexToPermutation(n: Int, x: BigInt): List[Int] = { indexToPermutation((0 until n).toList, x) }   def indexToPermutation(ns: List[Int], x: BigInt): List[Int] = ns match { case Nil => Nil case _ => { val (iBig, xNew) = x /% factorial(ns.size - 1) val i = iBig.toInt ns(i) :: indexToPermutation(ns.take(i) ++ ns.drop(i + 1), xNew) } }   def permutationToIndex[A](xs: List[A])(implicit ord: Ordering[A]): BigInt = xs match { case Nil => BigInt(0) case x :: rest => factorial(rest.size) * rest.count(ord.lt(_, x)) + permutationToIndex(rest) }
http://rosettacode.org/wiki/Pierpont_primes
Pierpont primes
A Pierpont prime is a prime number of the form: 2u3v + 1 for some non-negative integers u and v . A Pierpont prime of the second kind is a prime number of the form: 2u3v - 1 for some non-negative integers u and v . The term "Pierpont primes" is generally understood to mean the first definition, but will be called "Pierpont primes of the first kind" on this page to distinguish them. Task Write a routine (function, procedure, whatever) to find Pierpont primes of the first & second kinds. Use the routine to find and display here, on this page, the first 50 Pierpont primes of the first kind. Use the routine to find and display here, on this page, the first 50 Pierpont primes of the second kind If your language supports large integers, find and display here, on this page, the 250th Pierpont prime of the first kind and the 250th Pierpont prime of the second kind. See also Wikipedia - Pierpont primes OEIS:A005109 - Class 1 -, or Pierpont primes OEIS:A005105 - Class 1 +, or Pierpont primes of the second kind
#Prolog
Prolog
  ?- use_module(library(heaps)).   three_smooth(Lz) :- singleton_heap(H, 1, nothing), lazy_list(next_3smooth, 0-H, Lz).   next_3smooth(Top-H0, N-H2, N) :- min_of_heap(H0, Top, _), !, get_from_heap(H0, Top, _, H1), next_3smooth(Top-H1, N-H2, N). next_3smooth(_-H0, N-H3, N) :- get_from_heap(H0, N, _, H1), N2 is N * 2, N3 is N * 3, add_to_heap(H1, N2, nothing, H2), add_to_heap(H2, N3, nothing, H3).   first_kind(K) :- three_smooth(Ns), member(N, Ns), K is N + 1, prime(K).   second_kind(K) :- three_smooth(Ns), member(N, Ns), K is N - 1, prime(K).   show(Seq, N) :- format("The first ~w values of ~s are: ", [N, Seq]), once(findnsols(N, X, call(Seq, X), L)), write(L), nl, once(offset(249, call(Seq, TwoFifty))), format("The 250th value of ~w is ~w~n", [Seq, TwoFifty]).   main :- show(first_kind, 50), nl, show(second_kind, 50), nl, halt.   % primality checker -- Miller Rabin preceded with a round of trial divisions.   prime(N) :- integer(N), N > 1, divcheck( N, [ 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149], Result), ((Result = prime, !); miller_rabin_primality_test(N)).   divcheck(_, [], unknown) :- !. divcheck(N, [P|_], prime) :- P*P > N, !. divcheck(N, [P|Ps], State) :- N mod P =\= 0, divcheck(N, Ps, State).   miller_rabin_primality_test(N) :- bases(Bases, N), forall(member(A, Bases), strong_fermat_pseudoprime(N, A)).   miller_rabin_precision(16).   bases([31, 73], N) :- N < 9_080_191, !. bases([2, 7, 61], N) :- N < 4_759_123_141, !. bases([2, 325, 9_375, 28_178, 450_775, 9_780_504, 1_795_265_022], N) :- N < 18_446_744_073_709_551_616, !. % 2^64 bases(Bases, N) :- miller_rabin_precision(T), RndLimit is N - 2, length(Bases, T), maplist(random_between(2, RndLimit), Bases).   strong_fermat_pseudoprime(N, A) :- % miller-rabin strong pseudoprime test with base A. succ(Pn, N), factor_2s(Pn, S, D), X is powm(A, D, N), ((X =:= 1, !); \+ composite_witness(N, S, X)).   composite_witness(_, 0, _) :- !. composite_witness(N, K, X) :- X =\= N-1, succ(Pk, K), X2 is (X*X) mod N, composite_witness(N, Pk, X2).   factor_2s(N, S, D) :- factor_2s(0, N, S, D). factor_2s(S, D, S, D) :- D /\ 1 =\= 0, !. factor_2s(S0, D0, S, D) :- succ(S0, S1), D1 is D0 >> 1, factor_2s(S1, D1, S, D).   ?- main.  
http://rosettacode.org/wiki/Pick_random_element
Pick random element
Demonstrate how to pick a random element from a list.
#FreeBASIC
FreeBASIC
' FB 1.05.0 Win64   Dim a(0 To 9) As String = {"Zero", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine"}   Randomize Dim randInt As Integer   For i As Integer = 1 To 5 randInt = Int(Rnd * 10) Print a(randInt) Next Sleep
http://rosettacode.org/wiki/Pick_random_element
Pick random element
Demonstrate how to pick a random element from a list.
#Frink
Frink
a = ["one", "two", "three"] println[random[a]]
http://rosettacode.org/wiki/Primality_by_trial_division
Primality by trial division
Task Write a boolean function that tells whether a given integer is prime. Remember that   1   and all non-positive numbers are not prime. Use trial division. Even numbers greater than   2   may be eliminated right away. A loop from   3   to   √ n    will suffice,   but other loops are allowed. Related tasks   count in factors   prime decomposition   AKS test for primes   factors of an integer   Sieve of Eratosthenes   factors of a Mersenne number   trial factoring of a Mersenne number   partition an integer X into N primes   sequence of primes by Trial Division
#VBA
VBA
Option Explicit   Sub FirstTwentyPrimes() Dim count As Integer, i As Long, t(19) As String Do i = i + 1 If IsPrime(i) Then t(count) = i count = count + 1 End If Loop While count <= UBound(t) Debug.Print Join(t, ", ") End Sub   Function IsPrime(Nb As Long) As Boolean If Nb = 2 Then IsPrime = True ElseIf Nb < 2 Or Nb Mod 2 = 0 Then Exit Function Else Dim i As Long For i = 3 To Sqr(Nb) Step 2 If Nb Mod i = 0 Then Exit Function Next IsPrime = True End If End Function
http://rosettacode.org/wiki/Phrase_reversals
Phrase reversals
Task Given a string of space separated words containing the following phrase: rosetta code phrase reversal Reverse the characters of the string. Reverse the characters of each individual word in the string, maintaining original word order within the string. Reverse the order of each word of the string, maintaining the order of characters in each word. Show your output here. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#Frink
Frink
a = "rosetta code phrase reversal" println[reverse[a]] println[join["", map["reverse", wordList[a]]]] println[reverseWords[a]] // Built-in function // Alternately, the above could be // join["", reverse[wordList[a]]]  
http://rosettacode.org/wiki/Phrase_reversals
Phrase reversals
Task Given a string of space separated words containing the following phrase: rosetta code phrase reversal Reverse the characters of the string. Reverse the characters of each individual word in the string, maintaining original word order within the string. Reverse the order of each word of the string, maintaining the order of characters in each word. Show your output here. Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#Gambas
Gambas
Public Sub Main() Dim sString As String = "rosetta code phrase reversal" 'The string Dim sNewString, sTemp As String 'String variables Dim siCount As Short 'Counter Dim sWord As New String[] 'Word store   For siCount = Len(sString) DownTo 1 'Loop backwards through the string sNewString &= Mid(sString, sicount, 1) 'Add each character to the new string Next   Print "Original string = \t" & sString & "\n" & 'Print the original string "Reversed string = \t" & sNewString 'Print the reversed string   sNewString = "" 'Reset sNewString   For Each sTemp In Split(sString, " ") 'Split the original string by the spaces sWord.Add(sTemp) 'Add each word to sWord array Next   For siCount = sWord.max DownTo 0 'Loop backward through each word in sWord sNewString &= sWord[siCount] & " " 'Add each word to to sNewString Next   Print "Reversed word order = \t" & sNewString 'Print reversed word order   sNewString = "" 'Reset sNewString For Each sTemp In sWord 'For each word in sWord For siCount = Len(sTemp) DownTo 1 'Loop backward through the word sNewString &= Mid(sTemp, siCount, 1) 'Add the characters to sNewString Next sNewString &= " " 'Add a space at the end of each word Next   Print "Words reversed = \t" & sNewString 'Print words reversed   End
http://rosettacode.org/wiki/Permutations/Derangements
Permutations/Derangements
A derangement is a permutation of the order of distinct items in which no item appears in its original place. For example, the only two derangements of the three items (0, 1, 2) are (1, 2, 0), and (2, 0, 1). The number of derangements of n distinct items is known as the subfactorial of n, sometimes written as !n. There are various ways to calculate !n. Task Create a named function/method/subroutine/... to generate derangements of the integers 0..n-1, (or 1..n if you prefer). Generate and show all the derangements of 4 integers using the above routine. Create a function that calculates the subfactorial of n, !n. Print and show a table of the counted number of derangements of n vs. the calculated !n for n from 0..9 inclusive. Optional stretch goal   Calculate    !20 Related tasks   Anagrams/Deranged anagrams   Best shuffle   Left_factorials Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#EchoLisp
EchoLisp
  (lib 'list) ;; in-permutations (lib 'bigint)   ;; generates derangements by filtering out permutations (define (derangement? nums) ;; predicate (for/and ((n nums) (i (length nums))) (!= n i)))   (define (derangements n) (for/list ((p (in-permutations n))) #:when (derangement? p) p))   (define (count-derangements n) (for/sum ((p (in-permutations n))) #:when (derangement? p) 1))   ;; ;;  !n = (n - 1) (!(n-1) + !(n-2))   (define (!n n) (* (1- n) (+ (!n (1- n)) (!n (- n 2))))) (remember '!n #(1 0))    
http://rosettacode.org/wiki/Permutations_by_swapping
Permutations by swapping
Task Generate permutations of n items in which successive permutations differ from each other by the swapping of any two items. Also generate the sign of the permutation which is +1 when the permutation is generated from an even number of swaps from the initial state, and -1 for odd. Show the permutations and signs of three items, in order of generation here. Such data are of use in generating the determinant of a square matrix and any functions created should bear this in mind. Note: The Steinhaus–Johnson–Trotter algorithm generates successive permutations where adjacent items are swapped, but from this discussion adjacency is not a requirement. References Steinhaus–Johnson–Trotter algorithm Johnson-Trotter Algorithm Listing All Permutations Heap's algorithm [1] Tintinnalogia Related tasks   Matrix arithmetic   Gray code
#Elixir
Elixir
defmodule Permutation do def by_swap(n) do p = Enum.to_list(0..-n) |> List.to_tuple by_swap(n, p, 1) end   defp by_swap(n, p, s) do IO.puts "Perm: #{inspect for i <- 1..n, do: abs(elem(p,i))} Sign: #{s}" k = 0 |> step_up(n, p) |> step_down(n, p) if k > 0 do pk = elem(p,k) i = if pk>0, do: k+1, else: k-1 p = Enum.reduce(1..n, p, fn i,acc -> if abs(elem(p,i)) > abs(pk), do: put_elem(acc, i, -elem(acc,i)), else: acc end) pi = elem(p,i) p = put_elem(p,i,pk) |> put_elem(k,pi) # swap by_swap(n, p, -s) end end   defp step_up(k, n, p) do Enum.reduce(2..n, k, fn i,acc -> if elem(p,i)<0 and abs(elem(p,i))>abs(elem(p,i-1)) and abs(elem(p,i))>abs(elem(p,acc)), do: i, else: acc end) end   defp step_down(k, n, p) do Enum.reduce(1..n-1, k, fn i,acc -> if elem(p,i)>0 and abs(elem(p,i))>abs(elem(p,i+1)) and abs(elem(p,i))>abs(elem(p,acc)), do: i, else: acc end) end end   Enum.each(3..4, fn n -> Permutation.by_swap(n) IO.puts "" end)
http://rosettacode.org/wiki/Permutations_by_swapping
Permutations by swapping
Task Generate permutations of n items in which successive permutations differ from each other by the swapping of any two items. Also generate the sign of the permutation which is +1 when the permutation is generated from an even number of swaps from the initial state, and -1 for odd. Show the permutations and signs of three items, in order of generation here. Such data are of use in generating the determinant of a square matrix and any functions created should bear this in mind. Note: The Steinhaus–Johnson–Trotter algorithm generates successive permutations where adjacent items are swapped, but from this discussion adjacency is not a requirement. References Steinhaus–Johnson–Trotter algorithm Johnson-Trotter Algorithm Listing All Permutations Heap's algorithm [1] Tintinnalogia Related tasks   Matrix arithmetic   Gray code
#F.23
F#
  (*Implement Johnson-Trotter algorithm Nigel Galloway January 24th 2017*) module Ring let PlainChanges (N:'n[]) = seq{ let gn = [|for n in N -> 1|] let ni = [|for n in N -> 0|] let gel = Array.length(N)-1 yield N let rec _Ni g e l = seq{ match (l,g) with |_ when l<0 -> gn.[g] <- -gn.[g]; yield! _Ni (g-1) e (ni.[g-1] + gn.[g-1]) |(1,0) -> () |_ when l=g+1 -> gn.[g] <- -gn.[g]; yield! _Ni (g-1) (e+1) (ni.[g-1] + gn.[g-1]) |_ -> let n = N.[g-ni.[g]+e]; N.[g-ni.[g]+e] <- N.[g-l+e]; N.[g-l+e] <- n; yield N ni.[g] <- l; yield! _Ni gel 0 (ni.[gel] + gn.[gel])} yield! _Ni gel 0 1 }
http://rosettacode.org/wiki/Permutation_test
Permutation test
Permutation test You are encouraged to solve this task according to the task description, using any language you may know. A new medical treatment was tested on a population of n + m {\displaystyle n+m} volunteers, with each volunteer randomly assigned either to a group of n {\displaystyle n} treatment subjects, or to a group of m {\displaystyle m} control subjects. Members of the treatment group were given the treatment, and members of the control group were given a placebo. The effect of the treatment or placebo on each volunteer was measured and reported in this table. Table of experimental results Treatment group Control group 85 68 88 41 75 10 66 49 25 16 29 65 83 32 39 92 97 28 98 Write a program that performs a permutation test to judge whether the treatment had a significantly stronger effect than the placebo. Do this by considering every possible alternative assignment from the same pool of volunteers to a treatment group of size n {\displaystyle n} and a control group of size m {\displaystyle m} (i.e., the same group sizes used in the actual experiment but with the group members chosen differently), while assuming that each volunteer's effect remains constant regardless. Note that the number of alternatives will be the binomial coefficient ( n + m n ) {\displaystyle {\tbinom {n+m}{n}}} . Compute the mean effect for each group and the difference in means between the groups in every case by subtracting the mean of the control group from the mean of the treatment group. Report the percentage of alternative groupings for which the difference in means is less or equal to the actual experimentally observed difference in means, and the percentage for which it is greater. Note that they should sum to 100%. Extremely dissimilar values are evidence of an effect not entirely due to chance, but your program need not draw any conclusions. You may assume the experimental data are known at compile time if that's easier than loading them at run time. Test your solution on the data given above.
#Haskell
Haskell
binomial n m = (f !! n) `div` (f !! m) `div` (f !! (n - m)) where f = scanl (*) 1 [1..]   permtest treat ctrl = (fromIntegral less) / (fromIntegral total) * 100 where total = binomial (length avail) (length treat) less = combos (sum treat) (length treat) avail avail = ctrl ++ treat combos total n a@(x:xs) | total < 0 = binomial (length a) n | n == 0 = 0 | n > length a = 0 | n == length a = fromEnum (total < sum a) | otherwise = combos (total - x) (n - 1) xs + combos total n xs   main = let r = permtest [85, 88, 75, 66, 25, 29, 83, 39, 97] [68, 41, 10, 49, 16, 65, 32, 92, 28, 98] in do putStr "> : "; print r putStr "<=: "; print $ 100 - r
http://rosettacode.org/wiki/Percolation/Mean_cluster_density
Percolation/Mean cluster density
Percolation Simulation This is a simulation of aspects of mathematical percolation theory. For other percolation simulations, see Category:Percolation Simulations, or: 1D finite grid simulation Mean run density 2D finite grid simulations Site percolation | Bond percolation | Mean cluster density Let c {\displaystyle c} be a 2D boolean square matrix of n × n {\displaystyle n\times n} values of either 1 or 0 where the probability of any value being 1 is p {\displaystyle p} , (and of 0 is therefore 1 − p {\displaystyle 1-p} ). We define a cluster of 1's as being a group of 1's connected vertically or horizontally (i.e., using the Von Neumann neighborhood rule) and bounded by either 0 {\displaystyle 0} or by the limits of the matrix. Let the number of such clusters in such a randomly constructed matrix be C n {\displaystyle C_{n}} . Percolation theory states that K ( p ) {\displaystyle K(p)} (the mean cluster density) will satisfy K ( p ) = C n / n 2 {\displaystyle K(p)=C_{n}/n^{2}} as n {\displaystyle n} tends to infinity. For p = 0.5 {\displaystyle p=0.5} , K ( p ) {\displaystyle K(p)} is found numerically to approximate 0.065770 {\displaystyle 0.065770} ... Task Show the effect of varying n {\displaystyle n} on the accuracy of simulated K ( p ) {\displaystyle K(p)} for p = 0.5 {\displaystyle p=0.5} and for values of n {\displaystyle n} up to at least 1000 {\displaystyle 1000} . Any calculation of C n {\displaystyle C_{n}} for finite n {\displaystyle n} is subject to randomness, so an approximation should be computed as the average of t {\displaystyle t} runs, where t {\displaystyle t} ≥ 5 {\displaystyle 5} . For extra credit, graphically show clusters in a 15 × 15 {\displaystyle 15\times 15} , p = 0.5 {\displaystyle p=0.5} grid. Show your output here. See also s-Cluster on Wolfram mathworld.
#C
C
#include <stdio.h> #include <stdlib.h>   int *map, w, ww;   void make_map(double p) { int i, thresh = RAND_MAX * p; i = ww = w * w;   map = realloc(map, i * sizeof(int)); while (i--) map[i] = -(rand() < thresh); }   char alpha[] = "+.ABCDEFGHIJKLMNOPQRSTUVWXYZ" "abcdefghijklmnopqrstuvwxyz"; #define ALEN ((int)(sizeof(alpha) - 3))   void show_cluster(void) { int i, j, *s = map;   for (i = 0; i < w; i++) { for (j = 0; j < w; j++, s++) printf(" %c", *s < ALEN ? alpha[1 + *s] : '?'); putchar('\n'); } }   void recur(int x, int v) { if (x >= 0 && x < ww && map[x] == -1) { map[x] = v; recur(x - w, v); recur(x - 1, v); recur(x + 1, v); recur(x + w, v); } }   int count_clusters(void) { int i, cls;   for (cls = i = 0; i < ww; i++) { if (-1 != map[i]) continue; recur(i, ++cls); }   return cls; }   double tests(int n, double p) { int i; double k;   for (k = i = 0; i < n; i++) { make_map(p); k += (double)count_clusters() / ww; } return k / n; }   int main(void) { w = 15; make_map(.5); printf("width=15, p=0.5, %d clusters:\n", count_clusters()); show_cluster();   printf("\np=0.5, iter=5:\n"); for (w = 1<<2; w <= 1<<14; w<<=2) printf("%5d %9.6f\n", w, tests(5, .5));   free(map); return 0; }
http://rosettacode.org/wiki/Perfect_numbers
Perfect numbers
Write a function which says whether a number is perfect. A perfect number is a positive integer that is the sum of its proper positive divisors excluding the number itself. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself). Note:   The faster   Lucas-Lehmer test   is used to find primes of the form   2n-1,   all known perfect numbers can be derived from these primes using the formula   (2n - 1) × 2n - 1. It is not known if there are any odd perfect numbers (any that exist are larger than 102000). The number of   known   perfect numbers is   51   (as of December, 2018),   and the largest known perfect number contains  49,724,095  decimal digits. See also   Rational Arithmetic   Perfect numbers on OEIS   Odd Perfect showing the current status of bounds on odd perfect numbers.
#11l
11l
F perf(n) V sum = 0 L(i) 1 .< n I n % i == 0 sum += i R sum == n   L(i) 1..10000 I perf(i) print(i, end' ‘ ’)
http://rosettacode.org/wiki/Percolation/Bond_percolation
Percolation/Bond percolation
Percolation Simulation This is a simulation of aspects of mathematical percolation theory. For other percolation simulations, see Category:Percolation Simulations, or: 1D finite grid simulation Mean run density 2D finite grid simulations Site percolation | Bond percolation | Mean cluster density Given an M × N {\displaystyle M\times N} rectangular array of cells numbered c e l l [ 0.. M − 1 , 0.. N − 1 ] {\displaystyle \mathrm {cell} [0..M-1,0..N-1]} , assume M {\displaystyle M} is horizontal and N {\displaystyle N} is downwards. Each c e l l [ m , n ] {\displaystyle \mathrm {cell} [m,n]} is bounded by (horizontal) walls h w a l l [ m , n ] {\displaystyle \mathrm {hwall} [m,n]} and h w a l l [ m + 1 , n ] {\displaystyle \mathrm {hwall} [m+1,n]} ; (vertical) walls v w a l l [ m , n ] {\displaystyle \mathrm {vwall} [m,n]} and v w a l l [ m , n + 1 ] {\displaystyle \mathrm {vwall} [m,n+1]} Assume that the probability of any wall being present is a constant p {\displaystyle p} where 0.0 ≤ p ≤ 1.0 {\displaystyle 0.0\leq p\leq 1.0} Except for the outer horizontal walls at m = 0 {\displaystyle m=0} and m = M {\displaystyle m=M} which are always present. The task Simulate pouring a fluid onto the top surface ( n = 0 {\displaystyle n=0} ) where the fluid will enter any empty cell it is adjacent to if there is no wall between where it currently is and the cell on the other side of the (missing) wall. The fluid does not move beyond the horizontal constraints of the grid. The fluid may move “up” within the confines of the grid of cells. If the fluid reaches a bottom cell that has a missing bottom wall then the fluid can be said to 'drip' out the bottom at that point. Given p {\displaystyle p} repeat the percolation t {\displaystyle t} times to estimate the proportion of times that the fluid can percolate to the bottom for any given p {\displaystyle p} . Show how the probability of percolating through the random grid changes with p {\displaystyle p} going from 0.0 {\displaystyle 0.0} to 1.0 {\displaystyle 1.0} in 0.1 {\displaystyle 0.1} increments and with the number of repetitions to estimate the fraction at any given p {\displaystyle p} as t = 100 {\displaystyle t=100} . Use an M = 10 , N = 10 {\displaystyle M=10,N=10} grid of cells for all cases. Optionally depict fluid successfully percolating through a grid graphically. Show all output on this page.
#11l
11l
UInt32 seed = 0 F nonrandom()  :seed = 1664525 * :seed + 1013904223 R Int(:seed >> 16) / Float(FF'FF)   T Grid [[Int]] cell, hwall, vwall F (cell, hwall, vwall) .cell = cell .hwall = hwall .vwall = vwall   V (M, nn, t) = (10, 10, 100)   T PercolatedException (Int, Int) t F (t) .t = t   V HVF = ([‘ .’, ‘ _’], [‘:’, ‘|’], [‘ ’, ‘#’])   F newgrid(p) V hwall = (0 .. :nn).map(n -> (0 .< :M).map(m -> Int(nonrandom() < @@p))) V vwall = (0 .< :nn).map(n -> (0 .. :M).map(m -> (I m C (0, :M) {1} E Int(nonrandom() < @@p)))) V cell = (0 .< :nn).map(n -> (0 .< :M).map(m -> 0)) R Grid(cell, hwall, vwall)   F pgrid(grid, percolated) V (cell, hwall, vwall) = grid V (h, v, f) = :HVF L(n) 0 .< :nn print(‘ ’(0 .< :M).map(m -> @h[@hwall[@n][m]]).join(‘’)) print(‘#.) ’.format(n % 10)‘’(0 .. :M).map(m -> @v[@vwall[@n][m]]‘’@f[I m < :M {@cell[@n][m]} E 0]).join(‘’)[0 .< (len)-1]) V n = :nn print(‘ ’(0 .< :M).map(m -> @h[@hwall[@n][m]]).join(‘’)) I percolated != (-1, -1) V where = percolated[0] print(‘!) ’(‘ ’ * where)‘ ’f[1])   F flood_fill(m, n, &cell, hwall, vwall) -> N cell[n][m] = 1 I n < :nn - 1 & !hwall[n + 1][m] & !cell[n + 1][m] flood_fill(m, n + 1, &cell, hwall, vwall) E I n == :nn - 1 & !hwall[n + 1][m] X PercolatedException((m, n + 1)) I m & !vwall[n][m] & !cell[n][m - 1] flood_fill(m - 1, n, &cell, hwall, vwall) I m < :M - 1 & !vwall[n][m + 1] & !cell[n][m + 1] flood_fill(m + 1, n, &cell, hwall, vwall) I n != 0 & !hwall[n][m] & !cell[n - 1][m] flood_fill(m, n - 1, &cell, hwall, vwall)   F pour_on_top(Grid &grid) -> (Int, Int)? V n = 0 X.try L(m) 0 .< :M I grid.hwall[n][m] == 0 flood_fill(m, n, &grid.cell, grid.hwall, grid.vwall) X.catch PercolatedException ex R ex.t R N   V sample_printed = 0B [Float = Int] pcount L(p10) 11 V p = (10 - p10) / 10.0 pcount[p] = 0 L(tries) 0 .< t V grid = newgrid(p) (Int, Int)? percolated = pour_on_top(&grid) I percolated != N pcount[p]++ I !sample_printed print("\nSample percolating #. x #. grid".format(M, nn)) pgrid(grid, percolated ? (-1, -1)) sample_printed = 1B print("\n p: Fraction of #. tries that percolate through".format(t))   L(p, c) sorted(pcount.items()) print(‘#.1: #.’.format(p, c / Float(t)))
http://rosettacode.org/wiki/Percolation/Mean_run_density
Percolation/Mean run density
Percolation Simulation This is a simulation of aspects of mathematical percolation theory. For other percolation simulations, see Category:Percolation Simulations, or: 1D finite grid simulation Mean run density 2D finite grid simulations Site percolation | Bond percolation | Mean cluster density Let v {\displaystyle v} be a vector of n {\displaystyle n} values of either 1 or 0 where the probability of any value being 1 is p {\displaystyle p} ; the probability of a value being 0 is therefore 1 − p {\displaystyle 1-p} . Define a run of 1s as being a group of consecutive 1s in the vector bounded either by the limits of the vector or by a 0. Let the number of such runs in a given vector of length n {\displaystyle n} be R n {\displaystyle R_{n}} . For example, the following vector has R 10 = 3 {\displaystyle R_{10}=3} [1 1 0 0 0 1 0 1 1 1] ^^^ ^ ^^^^^ Percolation theory states that K ( p ) = lim n → ∞ R n / n = p ( 1 − p ) {\displaystyle K(p)=\lim _{n\to \infty }R_{n}/n=p(1-p)} Task Any calculation of R n / n {\displaystyle R_{n}/n} for finite n {\displaystyle n} is subject to randomness so should be computed as the average of t {\displaystyle t} runs, where t ≥ 100 {\displaystyle t\geq 100} . For values of p {\displaystyle p} of 0.1, 0.3, 0.5, 0.7, and 0.9, show the effect of varying n {\displaystyle n} on the accuracy of simulated K ( p ) {\displaystyle K(p)} . Show your output here. See also s-Run on Wolfram mathworld.
#D
D
import std.stdio, std.range, std.algorithm, std.random, std.math;   enum n = 100, p = 0.5, t = 500;   double meanRunDensity(in size_t n, in double prob) { return n.iota.map!(_ => uniform01 < prob) .array.uniq.sum / double(n); }   void main() { foreach (immutable p; iota(0.1, 1.0, 0.2)) { immutable limit = p * (1 - p); writeln; foreach (immutable n2; iota(10, 16, 2)) { immutable n = 2 ^^ n2; immutable sim = t.iota.map!(_ => meanRunDensity(n, p)) .sum / t; writefln("t=%3d, p=%4.2f, n=%5d, p(1-p)=%5.5f, " ~ "sim=%5.5f, delta=%3.1f%%", t, p, n, limit, sim, limit ? abs(sim - limit) / limit * 100 : sim*100); } } }
http://rosettacode.org/wiki/Percolation/Site_percolation
Percolation/Site percolation
Percolation Simulation This is a simulation of aspects of mathematical percolation theory. For other percolation simulations, see Category:Percolation Simulations, or: 1D finite grid simulation Mean run density 2D finite grid simulations Site percolation | Bond percolation | Mean cluster density Given an M × N {\displaystyle M\times N} rectangular array of cells numbered c e l l [ 0.. M − 1 , 0.. N − 1 ] {\displaystyle \mathrm {cell} [0..M-1,0..N-1]} assume M {\displaystyle M} is horizontal and N {\displaystyle N} is downwards. Assume that the probability of any cell being filled is a constant p {\displaystyle p} where 0.0 ≤ p ≤ 1.0 {\displaystyle 0.0\leq p\leq 1.0} The task Simulate creating the array of cells with probability p {\displaystyle p} and then testing if there is a route through adjacent filled cells from any on row 0 {\displaystyle 0} to any on row N {\displaystyle N} , i.e. testing for site percolation. Given p {\displaystyle p} repeat the percolation t {\displaystyle t} times to estimate the proportion of times that the fluid can percolate to the bottom for any given p {\displaystyle p} . Show how the probability of percolating through the random grid changes with p {\displaystyle p} going from 0.0 {\displaystyle 0.0} to 1.0 {\displaystyle 1.0} in 0.1 {\displaystyle 0.1} increments and with the number of repetitions to estimate the fraction at any given p {\displaystyle p} as t >= 100 {\displaystyle t>=100} . Use an M = 15 , N = 15 {\displaystyle M=15,N=15} grid of cells for all cases. Optionally depict a percolation through a cell grid graphically. Show all output on this page.
#Factor
Factor
USING: arrays combinators combinators.short-circuit formatting fry generalizations io kernel math math.matrices math.order math.ranges math.vectors prettyprint random sequences ; IN: rosetta-code.site-percolation   SYMBOLS: ▓ . v ;   : randomly-filled-matrix ( m n probability -- matrix ) [ random-unit > ▓ . ? ] curry make-matrix ;   : in-bounds? ( matrix loc -- ? ) [ dim { 1 1 } v- ] dip [ 0 rot between? ] 2map [ t = ] all? ;   : set-coord ( obj loc matrix -- ) [ reverse ] dip set-index ; : get-coord ( matrix loc -- elt ) swap [ first2 ] dip nth nth ;   : (can-percolate?) ( matrix loc -- ? ) { { [ 2dup in-bounds? not ] [ 2drop f ] } { [ 2dup get-coord { v ▓ } member? ] [ 2drop f ] } { [ 2dup second [ dim second 1 - ] dip = ] [ [ v ] 2dip swap set-coord t ] } [ 2dup get-coord . = [ [ v ] 2dip swap [ set-coord ] 2keep swap ] when { [ { 1 0 } v+ ] [ { 1 0 } v- ] [ { 0 1 } v+ ] [ { 0 1 } v- ] } [ (can-percolate?) ] map-compose 2|| ] } cond ;   : can-percolate? ( matrix -- ? ) dup dim first <iota> [ 0 2array (can-percolate?) ] with find drop >boolean ;   : show-sample ( -- ) f [ [ can-percolate? ] keep swap ] [ drop 15 15 0.6 randomly-filled-matrix ] do until "Sample percolation, p = 0.6" print simple-table. ;   : percolation-rate ( p -- rate ) [ 500 1 ] dip - '[ 15 15 _ randomly-filled-matrix can-percolate? ] replicate [ t = ] count 500 / ;   : site-percolation ( -- ) show-sample nl "Running 500 trials at each porosity:" print 10 [1,b] [ 10 / dup percolation-rate "p = %.1f: %.3f\n" printf ] each ;   MAIN: site-percolation
http://rosettacode.org/wiki/Percolation/Site_percolation
Percolation/Site percolation
Percolation Simulation This is a simulation of aspects of mathematical percolation theory. For other percolation simulations, see Category:Percolation Simulations, or: 1D finite grid simulation Mean run density 2D finite grid simulations Site percolation | Bond percolation | Mean cluster density Given an M × N {\displaystyle M\times N} rectangular array of cells numbered c e l l [ 0.. M − 1 , 0.. N − 1 ] {\displaystyle \mathrm {cell} [0..M-1,0..N-1]} assume M {\displaystyle M} is horizontal and N {\displaystyle N} is downwards. Assume that the probability of any cell being filled is a constant p {\displaystyle p} where 0.0 ≤ p ≤ 1.0 {\displaystyle 0.0\leq p\leq 1.0} The task Simulate creating the array of cells with probability p {\displaystyle p} and then testing if there is a route through adjacent filled cells from any on row 0 {\displaystyle 0} to any on row N {\displaystyle N} , i.e. testing for site percolation. Given p {\displaystyle p} repeat the percolation t {\displaystyle t} times to estimate the proportion of times that the fluid can percolate to the bottom for any given p {\displaystyle p} . Show how the probability of percolating through the random grid changes with p {\displaystyle p} going from 0.0 {\displaystyle 0.0} to 1.0 {\displaystyle 1.0} in 0.1 {\displaystyle 0.1} increments and with the number of repetitions to estimate the fraction at any given p {\displaystyle p} as t >= 100 {\displaystyle t>=100} . Use an M = 15 , N = 15 {\displaystyle M=15,N=15} grid of cells for all cases. Optionally depict a percolation through a cell grid graphically. Show all output on this page.
#Fortran
Fortran
  ! loosely translated from python. ! compilation: gfortran -Wall -std=f2008 thisfile.f08   !$ a=site && gfortran -o $a -g -O0 -Wall -std=f2008 $a.f08 && $a !100 trials per !Fill Fraction goal(%) simulated through paths(%) ! 0 0 ! 10 0 ! 20 0 ! 30 0 ! 40 0 ! 50 6 ! ! ! b b b b h j m m m ! b b b b b h h m m m m m ! b b b h h h m ! b h h h h h h h ! b b h h h h h h h h h ! b b b h h h h h h h h h h ! b b @ h h h h h h h ! @ @ h h h h h h h h ! @ @ @ @ h h h h ! @ @ @ @ h h h h h h ! @ @ @ h h h h h h h ! @ @ @ h h h h h h ! @ h h h h h h ! @ h h h h h h h ! @ @ h h h h h h h h h h ! 60 59 ! 70 97 ! 80 100 ! 90 100 ! 100 100   program percolation_site implicit none integer, parameter :: m=15,n=15,t=100 !integer, parameter :: m=2,n=2,t=8 integer(kind=1), dimension(m, n) :: grid real :: p integer :: i, ip, trial, successes logical :: success, unseen, q data unseen/.true./ write(6,'(i3,a11)') t,' trials per' write(6,'(a21,a30)') 'Fill Fraction goal(%)','simulated through paths(%)' do ip=0, 10 p = ip/10.0 successes = 0 do trial = 1, t call newgrid(grid, p) success = .false. do i=1, m q = walk(grid, i) ! deliberately compute all paths success = success .or. q end do if ((ip == 6) .and. unseen) then call display(grid) unseen = .false. end if successes = successes + merge(1, 0, success) end do write(6,'(9x,i3,24x,i3)')ip*10,nint(100*real(successes)/real(t)) end do   contains   logical function walk(grid, start) integer(kind=1), dimension(m,n), intent(inout) :: grid integer, intent(in) :: start walk = rwalk(grid, 1, start, int(start+1,1)) end function walk   recursive function rwalk(grid, i, j, k) result(through) logical :: through integer(kind=1), dimension(m,n), intent(inout) :: grid integer, intent(in) :: i, j integer(kind=1), intent(in) :: k logical, dimension(4) :: q !out of bounds through = .false. if (i < 1) return if (m < i) return if (j < 1) return if (n < j) return !visited or non-pore if (1_1 /= grid(i, j)) return !update grid and recurse with neighbors. deny 'shortcircuit' evaluation grid(i, j) = k q(1) = rwalk(grid,i+0,j+1,k) q(2) = rwalk(grid,i+0,j-1,k) q(3) = rwalk(grid,i+1,j+0,k) q(4) = rwalk(grid,i-1,j+0,k) !newly discovered outlet through = (i == m) .or. any(q) end function rwalk   subroutine newgrid(grid, probability) implicit none real :: probability integer(kind=1), dimension(m,n), intent(out) :: grid real, dimension(m,n) :: harvest call random_number(harvest) grid = merge(1_1, 0_1, harvest < probability) end subroutine newgrid   subroutine display(grid) integer(kind=1), dimension(m,n), intent(in) :: grid integer :: i, j, k, L character(len=n*2) :: lineout write(6,'(/)') lineout = ' ' do i=1,m do j=1,n k = j+j L = grid(i,j)+1 lineout(k:k) = ' @abcdefghijklmnopqrstuvwxyz'(L:L) end do write(6,*) lineout end do end subroutine display   end program percolation_site  
http://rosettacode.org/wiki/Permutations
Permutations
Task Write a program that generates all   permutations   of   n   different objects.   (Practically numerals!) Related tasks   Find the missing permutation   Permutations/Derangements The number of samples of size k from n objects. With   combinations and permutations   generation tasks. Order Unimportant Order Important Without replacement ( n k ) = n C k = n ( n − 1 ) … ( n − k + 1 ) k ( k − 1 ) … 1 {\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}} n P k = n ⋅ ( n − 1 ) ⋅ ( n − 2 ) ⋯ ( n − k + 1 ) {\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)} Task: Combinations Task: Permutations With replacement ( n + k − 1 k ) = n + k − 1 C k = ( n + k − 1 ) ! ( n − 1 ) ! k ! {\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}} n k {\displaystyle n^{k}} Task: Combinations with repetitions Task: Permutations with repetitions
#AArch64_Assembly
AArch64 Assembly
  /* ARM assembly AARCH64 Raspberry PI 3B */ /* program permutation64.s */   /*******************************************/ /* Constantes file */ /*******************************************/ /* for this file see task include a file in language AArch64 assembly */ .include "../includeConstantesARM64.inc"   /*********************************/ /* Initialized data */ /*********************************/ .data   sMessResult: .asciz "Value  : @\n" sMessCounter: .asciz "Permutations = @ \n" szCarriageReturn: .asciz "\n"   .align 4 TableNumber: .quad 1,2,3 .equ NBELEMENTS, (. - TableNumber) / 8 /*********************************/ /* UnInitialized data */ /*********************************/ .bss sZoneConv: .skip 24 /*********************************/ /* code section */ /*********************************/ .text .global main main: //entry of program ldr x0,qAdrTableNumber //address number table mov x1,NBELEMENTS //number of élements mov x10,0 //counter bl heapIteratif mov x0,x10 //display counter ldr x1,qAdrsZoneConv // bl conversion10S //décimal conversion ldr x0,qAdrsMessCounter ldr x1,qAdrsZoneConv //insert conversion bl strInsertAtCharInc bl affichageMess //display message   100: //standard end of the program mov x0,0 //return code mov x8,EXIT //request to exit program svc 0 //perform the system call   qAdrszCarriageReturn: .quad szCarriageReturn qAdrsMessResult: .quad sMessResult qAdrTableNumber: .quad TableNumber qAdrsMessCounter: .quad sMessCounter /******************************************************************/ /* permutation by heap iteratif (wikipedia) */ /******************************************************************/ /* x0 contains the address of table */ /* x1 contains the eléments number */ heapIteratif: stp x2,lr,[sp,-16]! // save registers stp x3,x4,[sp,-16]! // save registers stp x5,x6,[sp,-16]! // save registers stp x7,fp,[sp,-16]! // save registers tst x1,1 // odd ? add x2,x1,1 csel x2,x2,x1,ne // the stack must be a multiple of 16 lsl x7,x2,3 // 8 bytes by count sub sp,sp,x7 mov fp,sp mov x3,#0 mov x4,#0 // index 1: // init area counter str x4,[fp,x3,lsl 3] add x3,x3,#1 cmp x3,x1 blt 1b   bl displayTable add x10,x10,#1 mov x3,#0 // index 2: ldr x4,[fp,x3,lsl 3] // load count [i] cmp x4,x3 // compare with i bge 5f tst x3,#1 // even ? bne 3f ldr x5,[x0] // yes load value A[0] ldr x6,[x0,x3,lsl 3] // and swap with value A[i] str x6,[x0] str x5,[x0,x3,lsl 3] b 4f 3: ldr x5,[x0,x4,lsl 3] // load value A[count[i]] ldr x6,[x0,x3,lsl 3] // and swap with value A[i] str x6,[x0,x4,lsl 3] str x5,[x0,x3,lsl 3] 4: bl displayTable add x10,x10,1 add x4,x4,1 // increment count i str x4,[fp,x3,lsl 3] // and store on stack mov x3,0 // raz index b 2b // and loop 5: mov x4,0 // raz count [i] str x4,[fp,x3,lsl 3] add x3,x3,1 // increment index cmp x3,x1 // end ? blt 2b // no -> loop   add sp,sp,x7 // stack alignement 100: ldp x7,fp,[sp],16 // restaur 2 registers ldp x5,x6,[sp],16 // restaur 2 registers ldp x3,x4,[sp],16 // restaur 2 registers ldp x2,lr,[sp],16 // restaur 2 registers ret // return to address lr x30 /******************************************************************/ /* Display table elements */ /******************************************************************/ /* x0 contains the address of table */ displayTable: stp x1,lr,[sp,-16]! // save registers stp x2,x3,[sp,-16]! // save registers mov x2,x0 // table address mov x3,#0 1: // loop display table ldr x0,[x2,x3,lsl 3] ldr x1,qAdrsZoneConv bl conversion10S // décimal conversion ldr x0,qAdrsMessResult ldr x1,qAdrsZoneConv // insert conversion bl strInsertAtCharInc bl affichageMess // display message add x3,x3,1 cmp x3,NBELEMENTS - 1 ble 1b ldr x0,qAdrszCarriageReturn bl affichageMess mov x0,x2 100: ldp x2,x3,[sp],16 // restaur 2 registers ldp x1,lr,[sp],16 // restaur 2 registers ret // return to address lr x30 qAdrsZoneConv: .quad sZoneConv /********************************************************/ /* File Include fonctions */ /********************************************************/ /* for this file see task include a file in language AArch64 assembly */ .include "../includeARM64.inc"    
http://rosettacode.org/wiki/Perfect_shuffle
Perfect shuffle
A perfect shuffle (or faro/weave shuffle) means splitting a deck of cards into equal halves, and perfectly interleaving them - so that you end up with the first card from the left half, followed by the first card from the right half, and so on: 7♠ 8♠ 9♠ J♠ Q♠ K♠→7♠  8♠  9♠   J♠  Q♠  K♠→7♠ J♠ 8♠ Q♠ 9♠ K♠ When you repeatedly perform perfect shuffles on an even-sized deck of unique cards, it will at some point arrive back at its original order. How many shuffles this takes, depends solely on the number of cards in the deck - for example for a deck of eight cards it takes three shuffles: original: 1 2 3 4 5 6 7 8 after 1st shuffle: 1 5 2 6 3 7 4 8 after 2nd shuffle: 1 3 5 7 2 4 6 8 after 3rd shuffle: 1 2 3 4 5 6 7 8 The Task Write a function that can perform a perfect shuffle on an even-sized list of values. Call this function repeatedly to count how many shuffles are needed to get a deck back to its original order, for each of the deck sizes listed under "Test Cases" below. You can use a list of numbers (or anything else that's convenient) to represent a deck; just make sure that all "cards" are unique within each deck. Print out the resulting shuffle counts, to demonstrate that your program passes the test-cases. Test Cases input (deck size) output (number of shuffles required) 8 3 24 11 52 8 100 30 1020 1018 1024 10 10000 300
#ALGOL_68
ALGOL 68
# returns an array of the specified length, initialised to an ascending sequence of integers # OP DECK = ( INT length )[]INT: BEGIN [ 1 : length ]INT result; FOR i TO UPB result DO result[ i ] := i OD; result END # DECK # ;   # in-place shuffles the deck as per the task requirements # # LWB deck is assumed to be 1 # PROC shuffle = ( REF[]INT deck )VOID: BEGIN [ 1 : UPB deck ]INT result; INT left pos := 1; INT right pos := ( UPB deck OVER 2 ) + 1; FOR i FROM 2 BY 2 TO UPB result DO result[ left pos ] := deck[ i - 1 ]; result[ right pos ] := deck[ i ]; left pos +:= 1; right pos +:= 1 OD; FOR i TO UPB deck DO deck[ i ] := result[ i ] OD END # SHUFFLE # ;   # compares two integer arrays for equality # OP = = ( []INT a, b )BOOL: IF LWB a /= LWB b OR UPB a /= UPB b THEN # the arrays have different bounds # FALSE ELSE BOOL result := TRUE; FOR i FROM LWB a TO UPB a WHILE result := a[ i ] = b[ i ] DO SKIP OD; result FI # = # ;   # compares two integer arrays for inequality # OP /= = ( []INT a, b )BOOL: NOT ( a = b );   # returns the number of shuffles required to return a deck of the specified length # # back to its original state # PROC count shuffles = ( INT length )INT: BEGIN [] INT original deck = DECK length; [ 1 : length ]INT shuffled deck := original deck; INT count := 1; WHILE shuffle( shuffled deck ); shuffled deck /= original deck DO count +:= 1 OD; count END # count shuffles # ;   # test the shuffling # []INT lengths = ( 8, 24, 52, 100, 1020, 1024, 10 000 ); FOR l FROM LWB lengths TO UPB lengths DO print( ( whole( lengths[ l ], -8 ) + ": " + whole( count shuffles( lengths[ l ] ), -6 ), newline ) ) OD
http://rosettacode.org/wiki/Perlin_noise
Perlin noise
The   Perlin noise   is a kind of   gradient noise   invented by   Ken Perlin   around the end of the twentieth century and still currently heavily used in   computer graphics,   most notably to procedurally generate textures or heightmaps. The Perlin noise is basically a   pseudo-random   mapping of   R d {\displaystyle \mathbb {R} ^{d}}   into   R {\displaystyle \mathbb {R} }   with an integer   d {\displaystyle d}   which can be arbitrarily large but which is usually   2,   3,   or   4. Either by using a dedicated library or by implementing the algorithm, show that the Perlin noise   (as defined in 2002 in the Java implementation below)   of the point in 3D-space with coordinates     3.14,   42,   7     is     0.13691995878400012. Note: this result assumes 64 bit IEEE-754 floating point calculations. If your language uses a different floating point representation, make a note of it and calculate the value accurate to 15 decimal places, or your languages accuracy threshold if it is less. Trailing zeros need not be displayed.
#Factor
Factor
x floor >integer 255 bitand :> X y floor >integer 255 bitand :> Y z floor >integer 255 bitand :> Z