Sorting algorithms/Stooge sort

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Task
Sorting algorithms/Stooge sort
You are encouraged to solve this task according to the task description, using any language you may know.
This page uses content from Wikipedia. The original article was at Stooge sort. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)


Task

Show the   Stooge Sort   for an array of integers.


The Stooge Sort algorithm is as follows:

algorithm stoogesort(array L, i = 0, j = length(L)-1)
     if L[j] < L[i] then
         L[i]  L[j]
     if j - i > 1 then
         t := (j - i + 1)/3
         stoogesort(L, i  , j-t)
         stoogesort(L, i+t, j  )
         stoogesort(L, i  , j-t)
     return L



11l[edit]

Translation of: Python
F stoogesort(&l, i, j) -> N
   I l[j] < l[i]
      swap(&l[i], &l[j])
   I j - i > 1
      V t = (j - i + 1) I/ 3
      stoogesort(&l, i, j - t)
      stoogesort(&l, i + t, j)
      stoogesort(&l, i, j - t)

F stooge(&l)
   R stoogesort(&l, 0, l.len - 1)

V data = [1, 4, 5, 3, -6, 3, 7, 10, -2, -5, 7, 5, 9, -3, 7]
stooge(&data)
print(data)
Output:
[-6, -5, -3, -2, 1, 3, 3, 4, 5, 5, 7, 7, 7, 9, 10]

Action![edit]

Action! language does not support recursion. Therefore an iterative approach with a stack has been proposed.

DEFINE MAX_COUNT="100"
INT ARRAY stack(MAX_COUNT)
INT stackSize

PROC PrintArray(INT ARRAY a INT size)
  INT i

  Put('[)
  FOR i=0 TO size-1
  DO
    IF i>0 THEN Put(' ) FI
    PrintI(a(i))
  OD
  Put(']) PutE()
RETURN

PROC InitStack()
  stackSize=0
RETURN

BYTE FUNC IsEmpty()
  IF stackSize=0 THEN
    RETURN (1)
  FI
RETURN (0)

PROC Push(INT low,high)
  stack(stackSize)=low  stackSize==+1
  stack(stackSize)=high stackSize==+1
RETURN

PROC Pop(INT POINTER low,high)
  stackSize==-1 high^=stack(stackSize)
  stackSize==-1 low^=stack(stackSize)
RETURN

PROC StoogeSort(INT ARRAY a INT size)
  INT l,h,t,tmp

  InitStack()
  Push(0,size-1)
  WHILE IsEmpty()=0
  DO
    Pop(@l,@h)
    IF a(l)>a(h) THEN
      tmp=a(l) a(l)=a(h) a(h)=tmp
    FI
    IF h-l>1 THEN
      t=(h-l+1)/3
      Push(l,h-t)
      Push(l+t,h)
      Push(l,h-t)
    FI
  OD
RETURN

PROC Test(INT ARRAY a INT size)
  PrintE("Array before sort:")
  PrintArray(a,size)
  StoogeSort(a,size)
  PrintE("Array after sort:")
  PrintArray(a,size)
  PutE()
RETURN

PROC Main()
  INT ARRAY
    a(10)=[1 4 65535 0 3 7 4 8 20 65530],
    b(21)=[10 9 8 7 6 5 4 3 2 1 0
      65535 65534 65533 65532 65531
      65530 65529 65528 65527 65526],
    c(8)=[101 102 103 104 105 106 107 108],
    d(12)=[1 65535 1 65535 1 65535 1
      65535 1 65535 1 65535]
  
  Test(a,10)
  Test(b,21)
  Test(c,8)
  Test(d,12)
RETURN
Output:

Screenshot from Atari 8-bit computer

Array before sort:
[1 4 -1 0 3 7 4 8 20 -6]
Array after sort:
[-6 -1 0 1 3 4 4 7 8 20]

Array before sort:
[10 9 8 7 6 5 4 3 2 1 0 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10]
Array after sort:
[-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10]

Array before sort:
[101 102 103 104 105 106 107 108]
Array after sort:
[101 102 103 104 105 106 107 108]

Array before sort:
[1 -1 1 -1 1 -1 1 -1 1 -1 1 -1]
Array after sort:
[-1 -1 -1 -1 -1 -1 1 1 1 1 1 1]

Ada[edit]

Using slices and 'First / 'Last removes the need for I / J parameters.

with Ada.Text_IO;
procedure Stooge is
   type Integer_Array is array (Positive range <>) of Integer;
   procedure Swap (Left, Right : in out Integer) is
      Temp : Integer := Left;
   begin
      Left  := Right;
      Right := Temp;
   end Swap;
   procedure Stooge_Sort (List : in out Integer_Array) is
      T : Natural := List'Length / 3;
   begin
      if List (List'Last) < List (List'First) then
         Swap (List (List'Last), List (List'First));
      end if;
      if List'Length > 2 then
         Stooge_Sort (List (List'First     .. List'Last - T));
         Stooge_Sort (List (List'First + T .. List'Last));
         Stooge_Sort (List (List'First     .. List'Last - T));
      end if;
   end Stooge_Sort;
   Test_Array : Integer_Array := (1, 4, 5, 3, -6, 3, 7, 10, -2, -5, 7, 5, 9, -3, 7);
begin
   Stooge_Sort (Test_Array);
   for I in Test_Array'Range loop
      Ada.Text_IO.Put (Integer'Image (Test_Array (I)));
      if I /= Test_Array'Last then
         Ada.Text_IO.Put (", ");
      end if;
   end loop;
   Ada.Text_IO.New_Line;
end Stooge;
Output:
-6, -5, -3, -2,  1,  3,  3,  4,  5,  5,  7,  7,  7,  9,  10

ALGOL 68[edit]

Works with: ALGOL 68G version Any - tested with release 2.8.win32
# swaps the values of the two REF INTs #
PRIO =:= = 1;
OP   =:= = ( REF INT a, b )VOID: ( INT t := a; a := b; b := t );

# returns the array of INTs sorted via the stooge sort algorithm #
PROC stooge sort = ( []INT array )[]INT:
     BEGIN
         PROC stooge sort segment = ( REF[]INT l, INT i, j )VOID:
             BEGIN
                 IF l[j] < l[i] THEN l[ i ] =:= l[ j ] FI;
                 IF j - i > 1
                 THEN
                     INT t := (j - i + 1) OVER 3;
                     stooge sort segment( l, i,     j - t );
                     stooge sort segment( l, i + t, j     );
                     stooge sort segment( l, i,     j - t )
                 FI
             END # stooge sort segment # ;

         [ LWB array : UPB array ]INT result := array;
         stooge sort segment( result, LWB result, UPB result );
         result
     END # stooge sort # ;

# test the stooge sort #
[]INT data = ( 67, -201, 0, 9, 9, 231, 4 );
print( ( "before: ", data, newline, "after:  ", stooge sort( data ), newline ) )
Output:
before:         +67       -201         +0         +9         +9       +231         +4
after:         -201         +0         +4         +9         +9        +67       +231

AutoHotkey[edit]

StoogeSort(L, i:=1, j:=""){
	if !j
		j := L.MaxIndex()
	if (L[j] < L[i]){
		temp := L[i]
		L[i] := L[j]
		L[j] := temp
	}
	if (j - i > 1){
		t := floor((j - i + 1)/3)
		StoogeSort(L, i, j-t)
		StoogeSort(L, i+t, j)
		StoogeSort(L, i, j-t)
	}
	return L
}
Examples:
MsgBox % map(StoogeSort([123,51,6,73,3,-12,0]))
return

map(obj){
	for k, v in obj
		res .= v ","
	return trim(res, ",")
}
Outputs:
-12,0,3,6,51,73,123

BASIC[edit]

Works with: QuickBASIC version 7.1

This might work with older versions of QB, but that is untested. It definitely does not work with QBasic.

DECLARE SUB stoogesort (L() AS LONG, i AS LONG, j AS LONG)

RANDOMIZE TIMER

CONST arraysize = 10

DIM x(arraysize) AS LONG
DIM i AS LONG

PRINT "Before: ";
FOR i = 0 TO arraysize
    x(i) = INT(RND * 100)
    PRINT x(i); " ";
NEXT
PRINT

stoogesort x(), 0, arraysize

PRINT "After: ";
FOR i = 0 TO arraysize
    PRINT x(i); " ";
NEXT
PRINT

SUB stoogesort (L() AS LONG, i AS LONG, j AS LONG)
    IF L(j) < L(i) THEN SWAP L(i), L(j)
    IF (j - i) > 1 THEN
        DIM t AS LONG
        t = (j - i + 1) / 3
        stoogesort L(), i, j - t
        stoogesort L(), i + t, j
        stoogesort L(), i, j - t
    END IF
END SUB
Output:
Before:  15   42   21   50   33   65   40   43   20   25   19
After:  15   19   20   21   33   25   40   42   43   50   65
Before:  99   21   84   55   32   26   86   27   8   45   11
After:  8   11   21   26   27   32   45   55   84   86   99
Before:  11   50   11   37   97   94   92   70   92   57   88
After:  11   11   37   50   57   70   88   92   92   94   97

BBC BASIC[edit]

      DIM test%(9)
      test%() = 4, 65, 2, -31, 0, 99, 2, 83, 782, 1
      PROCstoogesort(test%(), 0, DIM(test%(),1))
      FOR i% = 0 TO 9
        PRINT test%(i%) ;
      NEXT
      PRINT
      END
      
      DEF PROCstoogesort(l%(), i%, j%)
      LOCAL t%
      IF l%(j%) < l%(i%) SWAP l%(i%), l%(j%)
      IF j% - i% > 1 THEN
        t% = (j% - i% + 1)/3
        PROCstoogesort(l%(), i%, j%-t%)
        PROCstoogesort(l%(), i%+t%, j%)
        PROCstoogesort(l%(), i%, j%-t%)
      ENDIF
      ENDPROC
Output:
       -31         0         1         2         2         4        65        83        99       782

BCPL[edit]

get "libhdr"

let stoogesort(L, i, j) be
$(  if L!j < L!i then
    $(  let x = L!i
        L!i := L!j
        L!j := x
    $)
    if j-i>1 then
    $(  let t = (j - i + 1)/3
        stoogesort(L, i, j-t)
        stoogesort(L, i+t, j)
        stoogesort(L, i, j-t)
    $)
$)

let write(s, A, len) be
$(  writes(s)
    for i=0 to len-1 do writed(A!i, 4)
    wrch('*N')
$)
    
let start() be
$(  let array = table 4,65,2,-31,0,99,2,83,782,1
    let length = 10    
    write("Before: ", array, length)
    stoogesort(array, 0, length-1)
    write("After:  ", array, length)
$)
Output:
Before:    4  65   2 -31   0  99   2  83 782   1
After:   -31   0   1   2   2   4  65  83  99 782

C[edit]

#include <stdio.h>

#define SWAP(r,s)  do{ t=r; r=s; s=t; } while(0)

void StoogeSort(int a[], int i, int j) 
{
   int t;
   
   if (a[j] < a[i]) SWAP(a[i], a[j]);
   if (j - i > 1)
   {
       t = (j - i + 1) / 3;
       StoogeSort(a, i, j - t);
       StoogeSort(a, i + t, j);
       StoogeSort(a, i, j - t);
   }
}
  
int main(int argc, char *argv[])
{
   int nums[] = {1, 4, 5, 3, -6, 3, 7, 10, -2, -5, 7, 5, 9, -3, 7};
   int i, n;
  
   n = sizeof(nums)/sizeof(int);
   StoogeSort(nums, 0, n-1);
   
   for(i = 0; i <= n-1; i++)
      printf("%5d", nums[i]);
   
   return 0;
}

C#[edit]

    public static void Sort<T>(List<T> list) where T : IComparable {
        if (list.Count > 1) {
            StoogeSort(list, 0, list.Count - 1);
        }
    }
    private static void StoogeSort<T>(List<T> L, int i, int j) where T : IComparable {
        if (L[j].CompareTo(L[i])<0) {
            T tmp = L[i];
            L[i] = L[j];
            L[j] = tmp;
        }
        if (j - i > 1) {
            int t = (j - i + 1) / 3;
            StoogeSort(L, i, j - t);
            StoogeSort(L, i + t, j);
            StoogeSort(L, i, j - t);
        }
    }

C++[edit]

#include <iostream>
#include <time.h>

//------------------------------------------------------------------------------
using namespace std;

//------------------------------------------------------------------------------
class stooge
{
public:
    void sort( int* arr, int start, int end )
    {
        if( arr[start] > arr[end - 1] ) swap( arr[start], arr[end - 1] );
	int n = end - start; if( n > 2 )
	{
	    n /= 3; sort( arr, start, end - n );
	    sort( arr, start + n, end ); sort( arr, start, end - n );
        }
    }
};
//------------------------------------------------------------------------------
int main( int argc, char* argv[] )
{
    srand( static_cast<unsigned int>( time( NULL ) ) ); stooge s; int a[80], m = 80; 
    cout << "before:\n";
    for( int x = 0; x < m; x++ ) { a[x] = rand() % 40 - 20;  cout << a[x] << " "; }
    s.sort( a, 0, m ); cout << "\n\nafter:\n"; 
    for( int x = 0; x < m; x++ ) cout << a[x] << " "; cout << "\n\n"; 
    return system( "pause" );
}
Output:
before:
5 -15 11 18 -14 -20 6 -4 -1 -8 12 -18 -12 -4 -10 -8 13 4 0 16 7 -13 -13 -1 11 -9
 13 -14 9 -19 -1 14 6 -4 7 -8 -15 -11 -9 3 10 3 -2 -5 12 -8 -2 10 -10 9 14 9 -12
 19 -16 -6 -13 -18 -3 -13 -12 8 -8 -10 -16 5 8 -10 -10 6 -14 -20 -16 7 15 11 -19
 -18 10 -15

after:
-20 -20 -19 -19 -18 -18 -18 -16 -16 -16 -15 -15 -15 -14 -14 -14 -13 -13 -13 -13
-12 -12 -12 -11 -10 -10 -10 -10 -10 -9 -9 -8 -8 -8 -8 -8 -6 -5 -4 -4 -4 -3 -2 -2
 -1 -1 -1 0 3 3 4 5 5 6 6 6 7 7 7 8 8 9 9 9 10 10 10 11 11 11 12 12 13 13 14 14
15 16 18 19

Clojure[edit]

(defn swap [v x y] 
   (assoc! v y (v x) x (v y)))

(defn stooge-sort
  ([v] (persistent! (stooge-sort (transient v) 0 (dec (count v)))))
  ([v i j]
    (if (> (v i) (v j)) (swap v i j) v)
    (if (> (- j i) 1)
      (let [t (int (Math/floor (/ (inc (- j i)) 3)))]
        (stooge-sort v i (- j t))
        (stooge-sort v (+ i t) j)
        (stooge-sort v i (- j t))))
    v))

COBOL[edit]

Works with: GNU Cobol
       >>SOURCE FREE
IDENTIFICATION DIVISION.
PROGRAM-ID. stooge-sort-test.

DATA DIVISION.
WORKING-STORAGE SECTION.
01  Arr-Len                             CONSTANT 7.

01  arr-area                            VALUE "00004001000020000005000230000000000".
    03  arr-elt                         PIC 9(5) OCCURS Arr-Len TIMES
                                        INDEXED BY arr-idx.

PROCEDURE DIVISION.
    DISPLAY "Unsorted: " NO ADVANCING
    PERFORM VARYING arr-idx FROM 1 BY 1 UNTIL Arr-Len < arr-idx
        DISPLAY arr-elt (arr-idx) " " NO ADVANCING
    END-PERFORM
    DISPLAY SPACE

    CALL "stooge-sort" USING arr-area, OMITTED, OMITTED

    DISPLAY "Sorted:   " NO ADVANCING
    PERFORM VARYING arr-idx FROM 1 BY 1 UNTIL Arr-Len < arr-idx
        DISPLAY arr-elt (arr-idx) " " NO ADVANCING
    END-PERFORM
    DISPLAY SPACE
    .
END PROGRAM stooge-sort-test.
    

IDENTIFICATION DIVISION.
PROGRAM-ID. stooge-sort RECURSIVE.

DATA DIVISION.
LOCAL-STORAGE SECTION.
01  Arr-Len                             CONSTANT 7.

01  i                                   PIC 99 COMP.
01  j                                   PIC 99 COMP.

01  temp                                PIC 9(5).

01  t                                   PIC 99 COMP.

LINKAGE SECTION.
01  arr-area.
    03  arr-elt                         PIC 9(5) OCCURS Arr-Len TIMES.

01  i-val                               PIC 99 COMP.
01  j-val                               PIC 99 COMP.

PROCEDURE DIVISION USING arr-area, OPTIONAL i-val, OPTIONAL j-val.
    IF i-val IS OMITTED
        MOVE 1 TO i
    ELSE
        MOVE i-val TO i
    END-IF
    IF j-val IS OMITTED
        MOVE Arr-Len TO j
    ELSE
        MOVE j-val TO j
    END-IF
    
    IF arr-elt (j) < arr-elt (i)
        MOVE arr-elt (i) TO temp
        MOVE arr-elt (j) TO arr-elt (i)
        MOVE temp TO arr-elt (j)
    END-IF   
    
    IF j - i + 1 >= 3
        COMPUTE t = (j - i + 1) / 3
        SUBTRACT t FROM j
        CALL "stooge-sort" USING arr-area, CONTENT i, j
        ADD t TO i, j
        CALL "stooge-sort" USING arr-area, CONTENT i, j
        SUBTRACT t FROM i, j
        CALL "stooge-sort" USING arr-area, CONTENT i, j
    END-IF
    .
END PROGRAM stooge-sort.
Output:
Unsorted: 00004 00100 00200 00005 00023 00000 00000
Sorted:   00000 00000 00004 00005 00023 00100 00200

Common Lisp[edit]

(defun stooge-sort (vector &optional (i 0) (j (1- (length vector))))
  (when (> (aref vector i) (aref vector j))
    (rotatef (aref vector i) (aref vector j)))
  (when (> (- j i) 1)
    (let ((third (floor (1+ (- j i)) 3)))
      (stooge-sort vector i (- j third))
      (stooge-sort vector (+ i third) j)
      (stooge-sort vector i (- j third))))
  vector)

D[edit]

import std.stdio, std.algorithm, std.array;

void stoogeSort(T)(T[] seq) pure nothrow {
    if (seq.back < seq.front)
        swap(seq.front, seq.back);

    if (seq.length > 2) {
        immutable m = seq.length / 3;
        seq[0 .. $ - m].stoogeSort();
        seq[m .. $].stoogeSort();
        seq[0 .. $ - m].stoogeSort();
    }
}

void main() {
    auto data = [1, 4, 5, 3, -6, 3, 7, 10, -2, -5];
    data.stoogeSort();
    writeln(data);
}
Output:
[-6, -5, -2, 1, 3, 3, 4, 5, 7, 10]

Eiffel[edit]

class
	STOOGE_SORT
feature
	stoogesort (ar: ARRAY[INTEGER]; i,j: INTEGER)
                -- Sorted array in ascending order.
	require
		ar_not_empty: ar.count >= 0
		i_in_range: i>=1
		j_in_range: j <= ar.count
		boundary_set: i<=j
	local
		t: REAL_64
		third: INTEGER
		swap: INTEGER
	do
		if ar[j]< ar[i] then
			swap:= ar[i]
			ar[i]:=ar[j]
			ar[j]:= swap
		end
		if j-i >1 then
			t:= (j-i+1)/3
			third:= t.floor
			stoogesort(ar, i, j-third)
			stoogesort(ar, i+third, j)
			stoogesort(ar, i, j-third)
		end
	end
end

Test:

class
	APPLICATION

create
	make

feature

	make
		do
			test := <<2, 5, 66, -2, 0, 7>>
			io.put_string ("%Nunsorted:%N")
			across
				test as ar
			loop
				io.put_string (ar.item.out + "%T")
			end
			create stoogesort
			stoogesort.stoogesort (test, 1, test.count)
			io.put_string ("%Nsorted:%N")
			across
				test as ar
			loop
				io.put_string (ar.item.out + "%T")
			end
		end

	test: ARRAY [INTEGER]

	stoogesort: STOOGE_SORT

end
Output:
unsorted:
2 5 66 -2 0 7
sorted:
-2 0 2 5 7 66

Elena[edit]

ELENA 4.x :

import extensions;
import system'routines;
 
extension op
{
    stoogeSort()
        = self.stoogeSort(0, self.Length - 1);
 
    stoogeSort(IntNumber i, IntNumber j) 
    {
        if(self[j]<self[i])
        {
            self.exchange(i,j)
        };
        if (j - i > 1)
        {
            int t := (j - i + 1) / 3;
            self.stoogeSort(i,j-t);
            self.stoogeSort(i+t,j);
            self.stoogeSort(i,j-t)
        }
    }
}
 
public program()
{
    var list := new Range(0, 15).selectBy:(n => randomGenerator.eval(20)).toArray();
 
    console.printLine("before:", list.asEnumerable());
    console.printLine("after:", list.stoogeSort().asEnumerable())
}
Output:
before:0,1,18,17,4,13,18,8,2,10,15,17,11,1,17
after:0,1,1,2,4,8,10,11,13,15,17,17,17,18,18

Elixir[edit]

defmodule Sort do
  def stooge_sort(list) do
    stooge_sort(List.to_tuple(list), 0, length(list)-1) |> Tuple.to_list
  end
  
  defp stooge_sort(tuple, i, j) do
    if (vj = elem(tuple, j)) < (vi = elem(tuple, i)) do
      tuple = put_elem(tuple,i,vj) |> put_elem(j,vi)
    end
    if j - i > 1 do
      t = div(j - i + 1, 3)
      tuple
      |> stooge_sort(i, j-t)
      |> stooge_sort(i+t, j)
      |> stooge_sort(i, j-t)
    else
      tuple
    end
  end
end

(for _ <- 1..20, do: :rand.uniform(20)) |> IO.inspect
|> Sort.stooge_sort |> IO.inspect
Output:
[18, 8, 19, 19, 17, 17, 1, 5, 17, 9, 13, 6, 7, 19, 1, 6, 11, 20, 17, 12]
[1, 1, 5, 6, 6, 7, 8, 9, 11, 12, 13, 17, 17, 17, 17, 18, 19, 19, 19, 20]

Euphoria[edit]

function stooge(sequence s, integer i, integer j)
    object temp
    integer t
    if compare(s[j], s[i]) < 0 then
        temp = s[i]
        s[i] = s[j]
        s[j] = temp
    end if
    if j - i > 1 then
        t = floor((j - i + 1)/3)
        s = stooge(s, i  , j-t)
        s = stooge(s, i+t, j  )
        s = stooge(s, i  , j-t)
    end if
    return s
end function

function stoogesort(sequence s)
    return stooge(s,1,length(s))
end function

constant s = rand(repeat(1000,10))

? s
? stoogesort(s)
Output:
{875,616,725,922,463,740,949,476,697,455}
{455,463,476,616,697,725,740,875,922,949}

Factor[edit]

USING: kernel locals math prettyprint sequences ;
IN: rosetta-code.stooge-sort

<PRIVATE

:: (stooge-sort) ( seq i j -- )
    j i [ seq nth ] bi@ < [
        j i seq exchange
    ] when
    j i - 1 > [
        j i - 1 + 3 /i :> t
        seq i j t - (stooge-sort)
        seq i t + j (stooge-sort)
        seq i j t - (stooge-sort)
    ] when ; 

PRIVATE>

: stooge-sort ( seq -- sortedseq )
    [ clone dup ] [ drop 0 ] [ length 1 - ] tri (stooge-sort) ;

: stooge-sort-demo ( -- )
    { 1 4 5 3 -6 3 7 10 -2 -5 } stooge-sort . ;

MAIN: stooge-sort-demo
Output:
{ -6 -5 -2 1 3 3 4 5 7 10 }

Fortran[edit]

Works with: Fortran version 90 and later
program Stooge
  implicit none

  integer :: i
  integer :: array(50) = (/ (i, i = 50, 1, -1) /) ! Reverse sorted array
  
  call Stoogesort(array)
  write(*,"(10i5)") array

contains

recursive subroutine Stoogesort(a)
  integer, intent(in out) :: a(:)
  integer :: j, t, temp
 
   j = size(a)
   if(a(j) < a(1)) then
     temp = a(j)
     a(j) = a(1)
     a(1) = temp
   end if

  if(j > 2) then
    t = j / 3
    call Stoogesort(a(1:j-t))
    call Stoogesort(a(1+t:j))
    call Stoogesort(a(1:j-t)) 
  end if

end subroutine
end program

FreeBASIC[edit]

' version 23-10-2016
' compile with: fbc -s console

Sub stoogesort(s() As Long, l As Long, r As Long)

    If s(r) < s(l) Then
        Swap s(r), s(l)
    End If

    If r - l > 1 Then
        Var t = (r - l +1) \ 3
        stoogesort(s(), l    , r - t)
        stoogesort(s(), l + t, r    )
        stoogesort(s(), l    , r - t)
    End If
End Sub

' ------=< MAIN >=------

Dim As Long i, array(-7 To 7)
Dim As Long a = LBound(array), b = UBound(array)

Randomize Timer
For i = a To b : array(i) = i  : Next
For i = a To b ' little shuffle
    Swap array(i), array(Int(Rnd * (b - a +1)) + a)
Next

Print "unsorted ";
For i = a To b : Print Using "####"; array(i); : Next : Print

stoogesort(array(), LBound(array), UBound(array))

Print "  sorted ";
For i = a To b : Print Using "####"; array(i); : Next : Print

' empty keyboard buffer
While Inkey <> "" : Wend
Print : Print "hit any key to end program"
Sleep
End
Output:
Unsorted
   0   3  -6   2   1  -4   7   5   6  -3   4  -7  -1  -5  -2

After heapsort
  -7  -6  -5  -4  -3  -2  -1   0   1   2   3   4   5   6   7

Go[edit]

package main

import "fmt"

var a = []int{170, 45, 75, -90, -802, 24, 2, 66}

func main() {
    fmt.Println("before:", a)
    stoogesort(a)
    fmt.Println("after: ", a)
    fmt.Println("nyuk nyuk nyuk")
}

func stoogesort(a []int) {
    last := len(a) - 1
    if a[last] < a[0] {
        a[0], a[last] = a[last], a[0]
    }
    if last > 1 {
        t := len(a) / 3
        stoogesort(a[:len(a)-t])
        stoogesort(a[t:])
        stoogesort(a[:len(a)-t])
    }
}

Haskell[edit]

import Data.List
import Control.Arrow
import Control.Monad

insertAt e k = uncurry(++).second ((e:).drop 1). splitAt k

swapElems :: [a] -> Int -> Int -> [a]
swapElems xs i j = insertAt (xs!!j) i $ insertAt (xs!!i) j xs 
	
stoogeSort [] = []
stoogeSort [x] = [x]
stoogeSort xs = doss 0 (length xs - 1) xs
doss :: (Ord a) => Int -> Int -> [a] -> [a]
doss i j xs
      | j-i>1 = doss i (j-t) $ doss (i+t) j $ doss i (j-t) xs'
      | otherwise = xs'
    where t = (j-i+1)`div`3
	  xs'
	    | xs!!j < xs!!i = swapElems xs i j
	    | otherwise = xs

Example:

*Main> stoogeSort [1, 4, 5, 3, -6, 3, 7, 10, -2, -5, 7, 5, 9, -3, 7]
[-6,-5,-3,-2,1,3,3,4,5,5,7,7,7,9,10]

Icon and Unicon[edit]

procedure main()              #: demonstrate various ways to sort a list and string 
   demosort(stoogesort,[3, 14, 1, 5, 9, 2, 6, 3],"qwerty")
end

procedure stoogesort(X,op,i,j)           #: return sorted list ascending(or descending)
local t 

   if /i := 0 then {
      j := *X
      op := sortop(op,X)                 # select how and what we sort
      }

   if op(X[j],X[i]) then
      X[i] :=: X[j]
   if j - i > 1 then {
      t := (j - i + 1) / 3
      X := stoogesort(X,op,i,j-t) 
      X := stoogesort(X,op,i+t,j)
      X := stoogesort(X,op,i,j-t)
      }
   return X                              # X must be returned and assigned to sort a string
end

Note: This example relies on the supporting procedures 'sortop', and 'demosort' in Bubble Sort. The full demosort exercises the named sort of a list with op = "numeric", "string", ">>" (lexically gt, descending), ">" (numerically gt, descending), a custom comparator, and also a string.

Output:
Abbreviated sample
Sorting Demo using procedure stoogesort
  on list : [ 3 14 1 5 9 2 6 3 ]
    with op = &null:         [ 1 2 3 3 5 6 9 14 ]   (0 ms)
  ...
  on string : "qwerty"
    with op = &null:         "eqrtwy"   (0 ms)

IS-BASIC[edit]

100 PROGRAM "StoogSrt.bas"
110 RANDOMIZE
120 NUMERIC ARRAY(5 TO 16)
130 CALL INIT(ARRAY)
140 CALL WRITE(ARRAY)
150 CALL STOOGESORT(ARRAY,LBOUND(ARRAY),UBOUND(ARRAY))
160 CALL WRITE(ARRAY)
170 DEF INIT(REF A)
180   FOR I=LBOUND(A) TO UBOUND(A)
190     LET A(I)=RND(99)+1
200   NEXT
210 END DEF
220 DEF WRITE(REF A)
230   FOR I=LBOUND(A) TO UBOUND(A)
240     PRINT A(I);
250   NEXT
260   PRINT
270 END DEF
280 DEF STOOGESORT(REF A,I,J)
290   NUMERIC T
300   IF A(J)<A(I) THEN LET T=A(J):LET A(J)=A(I):LET A(I)=T
310   IF J-I>1 THEN
320     LET T=IP((J-I+1)/3)
330     CALL STOOGESORT(A,I,J-T)
340     CALL STOOGESORT(A,I+T,J)
350     CALL STOOGESORT(A,I,J-T)
360   END IF
370 END DEF

J[edit]

swapElems=: |.@:{`[`]}

stoogeSort=: 3 : 0
  (0,<:#y) stoogeSort y
:
  if. >/x{y do. y=.x swapElems y end.
  if. 1<-~/x do.
    t=. <.3%~1+-~/x
    (x-0,t) stoogeSort (x+t,0) stoogeSort (x-0,t) stoogeSort y
  else. y end.
)

Example:

   (,: stoogeSort) ?~13
3 10 8 4 7 12 1 2 11 6  5  9  0
0  1 2 3 4  5 6 7  8 9 10 11 12

Java[edit]

import java.util.Arrays;

public class Stooge {
    public static void main(String[] args) {
        int[] nums = {1, 4, 5, 3, -6, 3, 7, 10, -2, -5};
        stoogeSort(nums);
        System.out.println(Arrays.toString(nums));
    }

    public static void stoogeSort(int[] L) {
        stoogeSort(L, 0, L.length - 1);
    }

    public static void stoogeSort(int[] L, int i, int j) {
        if (L[j] < L[i]) {
            int tmp = L[i];
            L[i] = L[j];
            L[j] = tmp;
        }
        if (j - i > 1) {
            int t = (j - i + 1) / 3;
            stoogeSort(L, i, j - t);
            stoogeSort(L, i + t, j);
            stoogeSort(L, i, j - t);
        }
    }
}
Output:
[-6, -5, -2, 1, 3, 3, 4, 5, 7, 10]

JavaScript[edit]

function stoogeSort (array, i, j) {
    if (j === undefined) {
        j = array.length - 1;
    }

    if (i === undefined) {
        i = 0;
    }

    if (array[j] < array[i]) {
        var aux = array[i];
        array[i] = array[j];
        array[j] = aux;
    }

    if (j - i > 1) {
        var t = Math.floor((j - i + 1) / 3);
        stoogeSort(array, i, j-t);
        stoogeSort(array, i+t, j);
        stoogeSort(array, i, j-t);
    }
};

Example:

arr = [9,1,3,10,13,4,2];
stoogeSort(arr);
console.log(arr);
Output:
[1, 2, 3, 4, 9, 10, 13]

jq[edit]

Works with: jq version 1.4
def stoogesort:
  def swap(i;j): .[i] as $t | .[i] = .[j] | .[j] = $t;
  
  # for efficiency, define an auxiliary function
  # that takes as input [L, i, j]
  def ss: .[1] as $i | .[2] as $j
     | .[0]
     | if .[$j] < .[$i] then swap($i;$j) else . end
     | if $j - $i > 1 then
          (($j - $i + 1) / 3 | floor) as $t
          | [., $i, $j-$t] | ss
	  | [., $i+$t, $j] | ss
	  | [., $i, $j-$t] | ss
       else .
       end;

  [., 0, length-1] | ss;

Example

([],
 [1],
 [1,2],
 [1,3,2,4],
 [1,4,5,3,-6,3,7,10,-2,-5]
) | stoogesort
Output:
$ jq -c -n -f stooge_sort.jq
[]
[1]
[1,2]
[1,2,3,4]
[-6,-5,-2,1,3,3,4,5,7,10]

Julia[edit]

Works with: Julia version 0.6
Translation of: Matlab
function stoogesort!(a::Array, i::Int=1, j::Int=length(a))
    if a[j] < a[i]
        a[[i, j]] = a[[j, i]];
    end

    if (j - i) > 1
        t = round(Int, (j - i + 1) / 3)
        a = stoogesort!(a, i,     j - t)
        a = stoogesort!(a, i + t, j)
        a = stoogesort!(a, i,     j - t)
    end

    return a
end

x = randn(10)
@show x stoogesort!(x)
Output:
x = [0.222881, -1.06902, -1.07703, 0.466872, 1.52261, -0.25279, -1.72147, -0.217577, -0.556917, 2.13601]
stoogesort!(x) = [-1.72147, -1.07703, -1.06902, -0.556917, -0.25279, -0.217577, 0.222881, 0.466872, 1.52261, 2.13601]

Kotlin[edit]

// version 1.1.0

fun stoogeSort(a: IntArray, i: Int, j: Int) {
    if (a[j] < a[i]) {
        val temp = a[j]
        a[j] = a[i]
        a[i] = temp
    }
    if (j - i > 1) {
        val t = (j - i + 1) / 3
        stoogeSort(a, i, j - t)
        stoogeSort(a, i + t, j)
        stoogeSort(a, i, j - t)
    }
}

fun main(args: Array<String>) {
    val a = intArrayOf(100, 2, 56, 200, -52, 3, 99, 33, 177, -199)
    println("Original : ${a.asList()}")
    stoogeSort(a, 0, a.size - 1)
    println("Sorted   : ${a.asList()}")  
}
Output:
Original : [100, 2, 56, 200, -52, 3, 99, 33, 177, -199]
Sorted   : [-199, -52, 2, 3, 33, 56, 99, 100, 177, 200]

Lua[edit]

An example using a Y combinator for anonymous recursion and made generic with an optional predicate parameter.

local Y = function (f)
  return (function(x) return x(x) end)(function(x) return f(function(...) return x(x)(...) end) end)
end

function stoogesort(L, pred)

  pred = pred or function(a,b) return a < b end

  Y(function(recurse)
    return function(i,j)
      if pred(L[j], L[i]) then
        L[j],L[i] = L[i],L[j]
      end
      if j - i > 1 then
        local t = math.floor((j - i + 1)/3)
        recurse(i,j-t)
        recurse(i+t,j)
        recurse(i,j-t)
      end
    end
  end)(1,#L)
  
  return L
end

print(unpack(stoogesort{9,7,8,5,6,3,4,2,1,0}))

Maple[edit]

swap := proc(arr, a, b)
	local temp := arr[a];
	arr[a] := arr[b];
	arr[b] := temp;
end proc:

stoogesort:= proc(arr, start_index, end_index)
	local cur;
	if (arr[end_index] < arr[start_index]) then
		swap(arr, start_index, end_index);
	end if;
	
	if  end_index - start_index > 1 then
		cur := trunc((end_index - start_index + 1)/3);
		stoogesort(arr, start_index, end_index - cur);
		stoogesort(arr, start_index + cur, end_index);
		stoogesort(arr, start_index, end_index - cur);
	end if;
	
	return arr;
end proc:


arr := Array([4, 2, 6, 1, 3, 7, 9, 5, 8]):
stoogesort(arr, 1, numelems(arr));
Output:
[1, 2, 3, 4, 5, 6, 7, 8, 9]


Mathematica/Wolfram Language[edit]

stoogeSort[lst_, I_, J_] := Module[{i = I, j = J, list = lst},
 If[list[[j]] < list[[i]], list[[{i,j}]] = list[[{j,i}]];] 
 If[(j-i) > 1, t = Round[(j-i+1)/3];
  list=stoogeSort[list,i,j-t];
  list=stoogeSort[list,i+t,j];
  list=stoogeSort[list,i,j-t];];
 list
]
Output:
stoogeSort[{3,2,9,6,8},1,5]
{2,3,6,8,9}

MATLAB / Octave[edit]

%Required inputs:
%i = 1
%j = length(list)
%
function list = stoogeSort(list,i,j)

    if list(j) < list(i)
        list([i j]) = list([j i]);
    end
    
    if (j - i) > 1
        t = round((j-i+1)/3);
        list = stoogeSort(list,i,j-t);
        list = stoogeSort(list,i+t,j);
        list = stoogeSort(list,i,j-t);
    end

end
Output:
>> stoogeSort([1 -6 4 -9],1,4)

ans =

    -9    -6     1     4

MAXScript[edit]

fn stoogeSort arr i: j: =
(
	if i == unsupplied do i = 1
	if j == unsupplied do j = arr.count
	
	if arr[j] < arr[i] do
	(
		swap arr[j] arr[i]
	)
	if j - i > 1 do
	(
		local  t = (j - i+1)/3
		arr = stoogeSort arr i:i j:(j-t)
		arr = stoogeSort arr i:(i+t) j:j
		arr = stoogeSort arr i:i j:(j-t)
	)
	return arr
)
Output:
a = for i in 1 to 15 collect random 1 20
#(10, 2, 1, 19, 18, 20, 18, 5, 13, 2, 13, 9, 7, 10, 6)
stoogeSort a
#(1, 2, 2, 5, 6, 7, 9, 10, 10, 13, 13, 18, 18, 19, 20)

NetRexx[edit]

/* NetRexx */
options replace format comments java crossref savelog symbols binary

iList = [int 1, 4, 5, 3, -6, 3, 7, 10, -2, -5, 7, 5, 9, -3, 7]
sList = Arrays.copyOf(iList, iList.length)

sList = stoogeSort(sList)

lists = [iList, sList]
loop ln = 0 to lists.length - 1
  cl = lists[ln]
  rpt = Rexx('')
  loop ct = 0 to cl.length - 1
    rpt = rpt cl[ct]
    end ct
    say '['rpt.strip().changestr(' ', ',')']'
  end ln

return

method stoogeSort(L_ = int[], i_ = 0, j_ = L_.length - 1) public static returns int[]

  if L_[j_] < L_[i_] then do
    Lt     = L_[i_]
    L_[i_] = L_[j_]
    L_[j_] = Lt
    end
  if j_ - i_ > 1 then do
    t_ = (j_ - i_ + 1) % 3
    L_ = stoogeSort(L_, i_, j_ - t_)
    L_ = stoogeSort(L_, i_ + t_, j_)
    L_ = stoogeSort(L_, i_, j_ - t_)
    end

  return L_
Output:
[1,4,5,3,-6,3,7,10,-2,-5,7,5,9,-3,7]
[-6,-5,-3,-2,1,3,3,4,5,5,7,7,7,9,10]

Nim[edit]

proc stoogeSort[T](a: var openarray[T], i, j: int) =
  if a[j] < a[i]: swap a[i], a[j]
  if j - i > 1:
    let t = (j - i + 1) div 3
    stoogeSort(a, i, j - t)
    stoogeSort(a, i + t, j)
    stoogeSort(a, i, j - t)

var a = @[4, 65, 2, -31, 0, 99, 2, 83, 782]
stoogeSort a, 0, a.high
echo a
Output:
@[-31, 0, 2, 2, 4, 65, 83, 99, 782]

Objeck[edit]

bundle Default {
  class Stooge {
    function : Main(args : String[]) ~ Nil {
      nums := [1, 4, 5, 3, -6, 3, 7, 10, -2, -5];
      StoogeSort(nums);
      each(i : nums) {
        IO.Console->Print(nums[i])->Print(",");
      };
      IO.Console->PrintLine();
    }
   
    function : native : StoogeSort(l : Int[]) ~ Nil {
      StoogeSort(l, 0, l->Size() - 1);
    }
   
    function : native : StoogeSort(l : Int[], i : Int, j : Int) ~ Nil {
       if(l[j] < l[i]) {
        tmp := l[i];
        l[i] := l[j];
        l[j] := tmp;
      };
      
      if(j - i > 1) {
        t := (j - i + 1) / 3;
        StoogeSort(l, i, j - t);
        StoogeSort(l, i + t, j);
        StoogeSort(l, i, j - t);
      };
    }
  }
}

OCaml[edit]

let swap ar i j =
  let tmp = ar.(i) in
  ar.(i) <- ar.(j);
  ar.(j) <- tmp

let stoogesort ar =
  let rec aux i j =
    if ar.(j) < ar.(i) then
      swap ar i j
    else if j - i > 1 then begin
      let t = (j - i + 1) / 3 in
      aux (i) (j-t);
      aux (i+t) (j);
      aux (i) (j-t);
    end
  in
  aux 0 (Array.length ar - 1)

testing:

let () =
  let ar = [| 3; 1; 7; 2; 6; 5; 4; 9; 8 |] in
  stoogesort ar;
  Array.iter (Printf.printf " %d") ar;
  print_newline()

ooRexx[edit]

Translation of: NetRexx
/* Rexx */

call demo
return
exit

-- -----------------------------------------------------------------------------
--  Stooge sort implementation
-- -----------------------------------------------------------------------------
::routine stoogeSort
  use arg rL_, i_ = 0, j_ = .nil
  if j_ = .nil then j_ = rL_~items() - 1

  if rL_~get(j_) < rL_~get(i_) then do
    Lt = rL_~get(i_)
    rL_~set(i_, rL_~get(j_))
    rL_~set(j_, Lt)
    end
  if j_ - i_ > 1 then do
    t_ = (j_ - i_ + 1) % 3
    rL_ = stoogeSort(rL_, i_, j_ - t_)
    rL_ = stoogeSort(rL_, i_ + t_, j_)
    rL_ = stoogeSort(rL_, i_, j_ - t_)
    end

  return rL_

-- -----------------------------------------------------------------------------
-- Demonstrate the implementation
-- -----------------------------------------------------------------------------
::routine demo

  iList = .nlist~of(1, 4, 5, 3, -6, 3, 7, 10, -2, -5, 7, 5, 9, -3, 7)
  sList = iList~copy()

  placesList = .nlist~of( -
      "UK  London",     "US  New York",   "US  Boston",     "US  Washington" -
    , "UK  Washington", "US  Birmingham", "UK  Birmingham", "UK  Boston"     -
  )

  sList = stoogeSort(sList)
  sortedList = stoogeSort(placesList~copy())

  iLists = .list~of(iList, sList)
  loop ln = 0 to iLists~items() - 1
    icl = iLists[ln]
    rpt = ''
    loop ct = 0 to icl~items() - 1
      rpt = rpt icl[ct]
      end ct
      say '['rpt~strip()~changestr(' ', ',')']'
    end ln

  say
  sLists = .list~of(placesList, sortedList)
  loop ln = 0 to sLists~items() - 1
    scl = sLists[ln]
    loop ct = 0 to scl~items() - 1
      say right(ct + 1, 3)':' scl[ct]
      end ct
      say
    end ln

  return

-- -----------------------------------------------------------------------------
-- Helper class.  Map get and set methods for easier conversion from java.util.List
-- -----------------------------------------------------------------------------
::class NList mixinclass List public

-- Map get() to at()
::method get
  use arg ix
  return self~at(ix)

-- Map set() to put()
::method set
  use arg ix, item
  self~put(item, ix)
  return
Output:
[1,4,5,3,-6,3,7,10,-2,-5,7,5,9,-3,7]
[-6,-5,-3,-2,1,3,3,4,5,5,7,7,7,9,10]

  1: UK  London
  2: US  New York
  3: US  Boston
  4: US  Washington
  5: UK  Washington
  6: US  Birmingham
  7: UK  Birmingham
  8: UK  Boston

  1: UK  Birmingham
  2: UK  Boston
  3: UK  London
  4: UK  Washington
  5: US  Birmingham
  6: US  Boston
  7: US  New York
  8: US  Washington

Oz[edit]

declare
  proc {StoogeSort Arr}
     proc {Swap I J}
        Tmp = Arr.I
     in
        Arr.I := Arr.J
        Arr.J := Tmp
     end
   
     proc {Sort I J}
        Size = J-I+1
     in
        if Arr.J < Arr.I then
           {Swap I J}
        end
        if Size >= 3 then
           Third = Size div 3
        in
           {Sort I J-Third}
           {Sort I+Third J}
           {Sort I J-Third}
        end
     end
  in
     {Sort {Array.low Arr} {Array.high Arr}}
  end

  Arr = {Tuple.toArray unit(1 4 5 3 ~6 3 7 10 ~2 ~5 7 5 9 ~3 7)}
in
  {System.printInfo "\nUnsorted: "}
  for I in {Array.low Arr}..{Array.high Arr} do
     {System.printInfo Arr.I#", "}
  end

  {StoogeSort Arr}

  {System.printInfo "\nSorted  : "}
  for I in {Array.low Arr}..{Array.high Arr} do
     {System.printInfo Arr.I#", "}
  end
Output:
Unsorted: 1, 4, 5, 3, -6, 3, 7, 10, -2, -5, 7, 5, 9, -3, 7, 
Sorted  : -6, -5, -3, -2, 1, 3, 3, 4, 5, 5, 7, 7, 7, 9, 10,

PARI/GP[edit]

stoogeSort(v)={
  local(v=v); \\ Give children access to v
  ss(1,#v);   \\ Sort
  v
}

ss(i,j)={
  my(t);
  if(v[j]<v[i],
    t=v[i];
    v[i]=v[j];
    v[j]=t
  );
  if(j-i > 1,
    t=(1+j-i)\3;
    ss(i,j-t);
    ss(i+t,j);
    ss(i,j-t)
  )
};

Pascal[edit]

program StoogeSortDemo;
 
type
  TIntArray = array of integer;

procedure stoogeSort(var m: TIntArray; i, j: integer);
  var
    t, temp: integer;
  begin
    if m[j] < m[i] then
    begin
      temp := m[j];
      m[j] := m[i];
      m[i] := temp;
    end;
    if j - i > 1 then
    begin
      t := (j - i + 1) div 3;
      stoogesort(m, i, j-t);
      stoogesort(m, i+t, j);
      stoogesort(m, i, j-t);
    end;
  end;

var
  data: TIntArray;
  i: integer;

begin
  setlength(data, 8);
  Randomize;
  writeln('The data before sorting:');
  for i := low(data) to high(data) do
  begin
    data[i] := Random(high(data));
    write(data[i]:4);
  end;
  writeln;
  stoogeSort(data, low(data), high(data));
  writeln('The data after sorting:');
  for i := low(data) to high(data) do
  begin
    write(data[i]:4);
  end;
  writeln;
end.
Output:
./StoogeSort
The data before sorting:
   6   1   2   1   5   2   1   5
The data after sorting:
   1   1   1   2   2   5   5   6

Perl[edit]

sub stooge {
        use integer;
        my ($x, $i, $j) = @_;

        $i //= 0;
        $j //= $#$x;

        if ( $x->[$j] < $x->[$i] ) {
                @$x[$i, $j] = @$x[$j, $i];
        }
        if ( $j - $i > 1 ) {
                my $t = ($j - $i + 1) / 3;
                stooge( $x, $i,      $j - $t );
                stooge( $x, $i + $t, $j      ); 
                stooge( $x, $i,      $j - $t );
        }
}


my @a = map (int rand(100), 1 .. 10);
print "Before @a\n";
stooge(\@a);
print "After  @a\n";

Phix[edit]

with javascript_semantics

function stoogesort(sequence s, integer i=1, j=length(s))
    if s[j]<s[i] then
        {s[i],s[j]} = {s[j],s[i]}
    end if
    if j-i>1 then
        integer t = floor((j-i+1)/3)
        s = stoogesort(s,i,  j-t)
        s = stoogesort(s,i+t,j  )
        s = stoogesort(s,i,  j-t)
    end if
    return s
end function

?stoogesort(shuffle(tagset(10)))
Output:
{1,2,3,4,5,6,7,8,9,10}

PHP[edit]

function stoogeSort(&$arr, $i, $j)
{
	if($arr[$j] < $arr[$i])
	{
		list($arr[$j],$arr[$i]) = array($arr[$i], $arr[$j]);
	}
	if(($j - $i) > 1)
	{
		$t = ($j - $i + 1) / 3;
		stoogesort($arr, $i, $j - $t);
		stoogesort($arr, $i + $t, $j);
		stoogesort($arr, $i, $j - $t);
	}
}

PicoLisp[edit]

(de stoogeSort (L N)
   (default N (length L))
   (let P (nth L N)
      (when (> (car L) (car P))
         (xchg L P) ) )
   (when (> N 2)
      (let D (/ N 3)
         (stoogeSort L (- N D))
         (stoogeSort (nth L (inc D)) (- N D))
         (stoogeSort L (- N D)) ) )
   L )

Test:

: (apply < (stoogeSort (make (do 100 (link (rand))))))
-> T

PL/I[edit]

stoogesort: procedure (L) recursive; /* 16 August 2010 */
   declare L(*) fixed binary;
   declare (i, j, t, temp) fixed binary;

   j = hbound(L,1);
   do i = lbound(L, 1) to j;
     if L(j) < L(i) then
         do; temp = L(i); L(i) = L(j); L(j) = temp; end;
     if j - i > 1 then
         do;
            t = (j - i + 1)/3;
            call stoogesort(L, i  , j-t);
            call stoogesort(L, i+t, j  );
            call stoogesort(L, i  , j-t);
         end;
   end;
end stoogesort;

PowerBASIC[edit]

PowerBASIC for DOS can use the BASIC code above, by removing CONST and changing all instances of arraysize to %arraysize (note the percent sign).

This version is closely based on the BASIC code above.

%arraysize = 10

SUB stoogesort (L() AS LONG, i AS LONG, j AS LONG)
    IF L(j) < L(i) THEN SWAP L(i), L(j)
    IF (j - i) > 1 THEN
        DIM t AS LONG
        t = (j - i + 1) / 3
        stoogesort L(), i, j - t
        stoogesort L(), i + t, j
        stoogesort L(), i, j - t
    END IF
END SUB

FUNCTION PBMAIN () AS LONG
    RANDOMIZE TIMER

    DIM x(%arraysize) AS LONG
    DIM i AS LONG, s AS STRING

    s = "Before: "
    FOR i = 0 TO %arraysize
        x(i) = INT(RND * 100)
        s = s & STR$(x(i)) & " "
    NEXT

    stoogesort x(), 0, %arraysize

    #IF %DEF(%PB_CC32)
        PRINT s
        s = ""
    #ELSE
        s = s & $CRLF
    #ENDIF

    s = s & "After: "
    FOR i = 0 TO %arraysize
        s = s & STR$(x(i)) & " "
    NEXT

    ? s
END FUNCTION
Output:
Before:  88  32  82  88  0  82  65  87  40  1  69
After:  0  1  32  40  65  69  82  82  87  88  88
Before:  60  64  95  11  52  26  7  4  51  67  47
After:  4  7  11  26  47  51  52  60  64  67  95
Before:  47  88  67  76  60  66  69  86  92  41  6
After:  6  41  47  60  66  67  69  76  88  86  92

PowerShell[edit]

Function StoogeSort( [Int32[]] $L )
{
	$i = 0
	$j = $L.length-1
	if( $L[$j] -lt $L[$i] )
	{
		$L[$i] = $L[$i] -bxor $L[$j]
		$L[$j] = $L[$i] -bxor $L[$j]
		$L[$i] = $L[$i] -bxor $L[$j]
	}
	if( $j -gt 1 )
	{
		$t = [int] ( ( $j + 1 ) / 3 )
		$k = $j - $t + 1
		[Array]::Copy( [Int32[]] ( StoogeSort( $L[0..( $j - $t ) ] ) ), $L, $k )
		[Array]::ConstrainedCopy( [Int32[]] ( StoogeSort( $L[$t..$j ] ) ), 0, $L, $t, $k )
		[Array]::Copy( [Int32[]] ( StoogeSort( $L[0..( $j - $t ) ] ) ), $L, $k )
	}
	$L
}

StoogeSort 9, 7, 5, 3, 1, 2, 4, 6, 8

PureBasic[edit]

Procedure Stooge_Sort(Array L.i(1), i=0 , j=0)
  If j=0
    j=ArraySize(L())
  EndIf
  If L(i)>L(j)
    Swap L(i), L(j)
  EndIf
  If j-i>1
    Protected t=(j-i+1)/3
    Stooge_Sort(L(), i,   j-t)
    Stooge_Sort(L(), i+t, j )
    Stooge_Sort(L(), i,   j-t)
  EndIf
EndProcedure
Implementation may be as
Define AmountOfPosts=(?Stop_Data-?Start_data)/SizeOf(Integer)
Dim    Xyz.i(AmountOfPosts)
CopyMemory(?Start_data, @Xyz(), ?Stop_Data-?Start_data)

Stooge_Sort(Xyz())

For i=0 To ArraySize(Xyz())
  Debug Xyz(i)
Next i

DataSection
  Start_data:
  Data.i  1, 4, 5, 3, -6, 3, 7, 10, -2, -5, 7, 5, 9, -3, 7
  Stop_Data:
EndDataSection

Python[edit]

>>> data = [1, 4, 5, 3, -6, 3, 7, 10, -2, -5, 7, 5, 9, -3, 7]
>>> def stoogesort(L, i=0, j=None):
	if j is None:
		j = len(L) - 1
	if L[j] < L[i]:
		L[i], L[j] = L[j], L[i]
	if j - i > 1:
		t = (j - i + 1) // 3
		stoogesort(L, i  , j-t)
		stoogesort(L, i+t, j  )
		stoogesort(L, i  , j-t)
	return L

>>> stoogesort(data)
[-6, -5, -3, -2, 1, 3, 3, 4, 5, 5, 7, 7, 7, 9, 10]

This alternate solution uses a wrapper function to compute the initial value of j rather than detecting the sentinel value None.

>>> def stoogesort(L, i, j):
	if L[j] < L[i]:
		L[i], L[j] = L[j], L[i]
	if j - i > 1:
		t = (j - i + 1) // 3
		stoogesort(L, i  , j-t)
		stoogesort(L, i+t, j  )
		stoogesort(L, i  , j-t)
	return L

>>> def stooge(L): return stoogesort(L, 0, len(L) - 1)

>>> data = [1, 4, 5, 3, -6, 3, 7, 10, -2, -5, 7, 5, 9, -3, 7]
>>> stooge(data)
[-6, -5, -3, -2, 1, 3, 3, 4, 5, 5, 7, 7, 7, 9, 10]

Quackery[edit]

  [ 2 * 3 /mod 0 > + ]       is twothirds  ( n --> n )

  [ dup 0 peek over -1 peek
    2dup > iff
      [ rot 0 poke -1 poke ]
    else 2drop ]             is swapends   ( [ --> [ )

  [ swapends
    dup size 3 < if done
    dup size twothirds split
    swap recurse swap join
    dup size 3 / split
    recurse join
    dup size twothirds split
    swap recurse swap join ] is stoogesort ( [ --> [ )

  [] 33 times [ 90 random 10 + join ]
  dup echo cr
  stoogesort echo
Output:
[ 32 45 68 88 88 89 45 20 86 74 31 91 24 77 87 91 89 76 41 76 84 14 99 72 98 73 79 11 22 75 66 27 34 ]
[ 11 14 20 22 24 27 31 32 34 41 45 45 66 68 72 73 74 75 76 76 77 79 84 86 87 88 88 89 89 91 91 98 99 ]

R[edit]

stoogesort = function(vect) {
	i = 1
	j = length(vect)
	if(vect[j] < vect[i])  vect[c(j, i)] = vect[c(i, j)]
	if(j - i > 1) {
		t = (j - i + 1) %/% 3
		vect[i:(j - t)] = stoogesort(vect[i:(j - t)])
		vect[(i + t):j] = stoogesort(vect[(i + t):j])
		vect[i:(j - t)] = stoogesort(vect[i:(j - t)])
	}
	vect
}

v = sample(21, 20)
k = stoogesort(v)
v
k
Output:
 [1] 13  5 20 16 11 19 17  7  9 14 21 18  2 10  1  6  8  4 15 12
 [1]  1  2  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20 21

Racket[edit]

#lang racket
(define (stooge-sort xs [i 0] [j (- (vector-length xs) 1)])
  (define (x i) (vector-ref xs i))
  (define (x! i v) (vector-set! xs i v))
  (define (swap! i j) (define t (x i)) (x! i (x j)) (x! j t))
  (when (> (x i) (x j)) (swap! i j))
  (when (> (- j i) 1)
    (define t (quotient (+ j (- i) 1) 3))
    (stooge-sort xs i (- j t))
    (stooge-sort xs (+ i t) j)
    (stooge-sort xs i (- j t)))
  xs)

Raku[edit]

(formerly Perl 6)

sub stoogesort( @L, $i = 0, $j = @L.end ) {
    @L[$j,$i] = @L[$i,$j] if @L[$i] > @L[$j];

    my $interval = $j - $i;
    
    if $interval > 1 {
         my $t = ( $interval + 1 ) div 3;
         stoogesort( @L, $i   , $j-$t );
         stoogesort( @L, $i+$t, $j    );
         stoogesort( @L, $i   , $j-$t );
    }
    return @L;
}

my @L = 1, 4, 5, 3, -6, 3, 7, 10, -2, -5;

stoogesort(@L).Str.say;

REXX[edit]

This REXX example starts an array at element zero   (but any integer could be used);   a zero-
based index was used because the algorithm shown in the Rosetta Code task used zero.

/*REXX program sorts  an  integer array   @.   [the first element starts at index zero].*/
parse arg N .                                    /*obtain an optional argument from C.L.*/
if N=='' | N==","  then N=19                     /*Not specified?  Then use the default.*/
call gen@                                        /*generate a type of scattered array.  */
call show    'before sort'                       /*show the   before   array elements.  */
say copies('▒', wN+wV+ 50)                       /*show a separator line (between shows)*/
call stoogeSort  0, N                            /*invoke the  Stooge Sort.             */
call show    ' after sort'                       /*show the    after   array elements.  */
exit                                             /*stick a fork in it,  we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
gen@: wV= 0;   do k=0  to N;      @.k= k*2 + k*-1**k;     if @.k//7==0  then @.k= -100 - k
               wV= max(wV, length(@.k) );  end;        wN=length(N);                return
/*──────────────────────────────────────────────────────────────────────────────────────*/
show: do j=0 to N; say right('element',22) right(j,wN) arg(1)":" right(@.j,wV); end;return
/*──────────────────────────────────────────────────────────────────────────────────────*/
stoogeSort: procedure expose @.;  parse arg i,j                  /*sort from  I ───► J. */
            if @.j<@.i  then parse value @.i @.j  with  @.j @.i  /*swap  @.i  with  @.j */
            if j-i>1    then do;   t=(j-i+1) % 3                 /*%:  integer division.*/
                                   call stoogeSort  i  ,  j-t    /*invoke recursively.  */
                                   call stoogeSort  i+t,  j      /*   "        "        */
                                   call stoogeSort  i  ,  j-t    /*   "        "        */
                             end
            return
output   when using the default (internal generated) inputs:

(Shown at three-quarter size.)

               element  0 before sort: -100
               element  1 before sort:    1
               element  2 before sort:    6
               element  3 before sort:    3
               element  4 before sort:   12
               element  5 before sort:    5
               element  6 before sort:   18
               element  7 before sort: -107
               element  8 before sort:   24
               element  9 before sort:    9
               element 10 before sort:   30
               element 11 before sort:   11
               element 12 before sort:   36
               element 13 before sort:   13
               element 14 before sort: -114
               element 15 before sort:   15
               element 16 before sort:   48
               element 17 before sort:   17
               element 18 before sort:   54
               element 19 before sort:   19
▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒
               element  0  after sort: -114
               element  1  after sort: -107
               element  2  after sort: -100
               element  3  after sort:    1
               element  4  after sort:    3
               element  5  after sort:    5
               element  6  after sort:    6
               element  7  after sort:    9
               element  8  after sort:   11
               element  9  after sort:   12
               element 10  after sort:   13
               element 11  after sort:   15
               element 12  after sort:   17
               element 13  after sort:   18
               element 14  after sort:   19
               element 15  after sort:   24
               element 16  after sort:   30
               element 17  after sort:   36
               element 18  after sort:   48
               element 19  after sort:   54

Ring[edit]

test = [4, 65, 2, -31, 0, 99, 2, 83, 782, 1]
stoogeSort(test, 1, len(test))
for i = 1 to 10
    see "" + test[i] + " "
next
see nl
 
func stoogeSort list, i, j
     if list[j] < list[i]
        temp = list[i]
        list[i] = list[j]
        list[j] = temp ok
     if j - i > 1 
        t = (j - i + 1)/3
        stoogeSort(list, i, j-t)
        stoogeSort(list, i+t, j)
        stoogeSort(list, i, j-t) ok
     return list

Output:

-31 0 1 2 2 4 65 83 99 782

Ruby[edit]

class Array
  def stoogesort
    self.dup.stoogesort!
  end

  def stoogesort!(i = 0, j = self.length-1)
    if self[j] < self[i]
      self[i], self[j] = self[j], self[i]
    end
    if j - i > 1
      t = (j - i + 1)/3
      stoogesort!(i, j-t)
      stoogesort!(i+t, j)
      stoogesort!(i, j-t)
    end
    self
  end
end

p [1,4,5,3,-6,3,7,10,-2,-5].stoogesort
Output:
[-6, -5, -2, 1, 3, 3, 4, 5, 7, 10]

Rust[edit]

fn stoogesort<E>(a: &mut [E])
    where E: PartialOrd
{
    let len = a.len();

    if a.first().unwrap() > a.last().unwrap() {
        a.swap(0, len - 1);
    }
    if len - 1 > 1 {
        let t = len / 3;
        stoogesort(&mut a[..len - 1]);
        stoogesort(&mut a[t..]);
        stoogesort(&mut a[..len - 1]);
    }
}

fn main() {
    let mut numbers = vec![1_i32, 9, 4, 7, 6, 5, 3, 2, 8];
    println!("Before: {:?}", &numbers);
    stoogesort(&mut numbers);
    println!("After: {:?}", &numbers);
}

Scala[edit]

object StoogeSort extends App {
  def stoogeSort(a: Array[Int], i: Int, j: Int) {
    if (a(j) < a(i)) {
      val temp = a(j)
      a(j) = a(i)
      a(i) = temp
    }
    if (j - i > 1) {
      val t = (j - i + 1) / 3
      stoogeSort(a, i, j - t)
      stoogeSort(a, i + t, j)
      stoogeSort(a, i, j - t)
    }
  }

  val a = Array(100, 2, 56, 200, -52, 3, 99, 33, 177, -199)
  println(s"Original : ${a.mkString(", ")}")
  stoogeSort(a, 0, a.length - 1)
  println(s"Sorted   : ${a.mkString(", ")}")
}

See it running in your browser by Scastie (JVM).

Sidef[edit]

func stooge(x, i, j) {
    if (x[j] < x[i]) {
        x.swap(i, j)
    }

    if (j-i > 1) {
        var t = ((j - i + 1) / 3)
        stooge(x, i,     j - t)
        stooge(x, i + t, j    )
        stooge(x, i,     j - t)
    }
}

var a = 10.of { 100.irand }

say "Before #{a}"
stooge(a, 0, a.end)
say "After  #{a}"

Smalltalk[edit]

Works with: GNU Smalltalk
OrderedCollection extend [
    stoogeSortFrom: i to: j [
	(self at: j) < (self at: i)
	  ifTrue: [ self swapElement: i with: j ].
	j - i > 1
          ifTrue: [
	      |t| t := (j - i + 1)//3.
	      self stoogeSortFrom: i to: (j-t).
	      self stoogeSortFrom: (i+t) to: j.
	      self stoogeSortFrom: i to: (j-t)
          ]
    ]
    stoogeSort [ self stoogeSortFrom: 1 to: (self size) ]
    swapElement: i with: j [
	|t| t := self at: i.
        self at: i put: (self at: j).
	self at: j put: t
    ]
].

|test|
test := #( 1 4 5 3 -6 3 7 10 -2 -5) asOrderedCollection.
test stoogeSort.
test printNl.

Here is a "functional" variation (a 1:1 adaption of the original algorithm):

stoogesort := [:L :i :j |
     (L at:i) > (L at:j) ifTrue:[
         L swap:i with:j
     ].
     (j - i + 1) > 2 ifTrue:[
         t := ((j - i + 1) / 3) floor.
         stoogesort value:L value:i value:j-t.
         stoogesort value:L value:i+t value:j.
         stoogesort value:L value:i value:j-t.
     ].
].

a := #(1 4 5 3 -6 3 7 10 -2 -5 7 5 9 -3 7)  copy.
stoogesort value:a value:1 value:a size.
Transcript showCR:a

Output:

#(-6 -5 -3 -2 1 3 3 4 5 5 7 7 7 9 10)

Swift[edit]

func stoogeSort(inout arr:[Int], _ i:Int = 0, var _ j:Int = -1) {
    if j == -1 {
        j = arr.count - 1
    }
    
    if arr[i] > arr[j] {
        swap(&arr[i], &arr[j])
    }
    
    if j - i > 1 {
        let t = (j - i + 1) / 3
        stoogeSort(&arr, i, j - t)
        stoogeSort(&arr, i + t, j)
        stoogeSort(&arr, i, j - t)
    }
}

var a = [-4, 2, 5, 2, 3, -2, 1, 100, 20]

stoogeSort(&a)

println(a)
Output:
[-4, -2, 1, 2, 2, 3, 5, 20, 100]

Tcl[edit]

Works with: Tcl version 8.5
package require Tcl 8.5

proc stoogesort {L {i 0} {j -42}} {
   if {$j == -42} {# Magic marker
      set j [expr {[llength $L]-1}]
   }
   set Li [lindex $L $i]
   set Lj [lindex $L $j]
   if {$Lj < $Li} {
      lset L $i $Lj
      lset L $j $Li
   }      
   if {$j-$i > 1} {
      set t [expr {($j-$i+1)/3}]
      set L [stoogesort $L $i [expr {$j-$t}]]
      set L [stoogesort $L [expr {$i+$t}] $j]
      set L [stoogesort $L $i [expr {$j-$t}]]
   }
   return $L
}

stoogesort {1 4 5 3 -6 3 7 10 -2 -5}
Output:
-6 -5 -2 1 3 3 4 5 7 10

uBasic/4tH[edit]

Translation of: BBC BASIC
PRINT "Stooge sort:"
  n = FUNC (_InitArray)
  PROC _ShowArray (n)
  PROC _Stoogesort (n)
  PROC _ShowArray (n)
PRINT
 
END
 

_InnerStooge PARAM(2)                  ' Stoogesort
  LOCAL(1)

  IF @(b@) < @(a@) Then Proc _Swap (a@, b@)
  IF b@ - a@ > 1 THEN
    c@ = (b@ - a@ + 1)/3
    PROC _InnerStooge (a@, b@-c@)
    PROC _InnerStooge (a@+c@, b@)
    PROC _InnerStooge (a@, b@-c@)
  ENDIF
RETURN


_Stoogesort PARAM(1)
  PROC _InnerStooge (0, a@ -  1)
RETURN
 
 
_Swap PARAM(2)                         ' Swap two array elements
  PUSH @(a@)
  @(a@) = @(b@)
  @(b@) = POP()
RETURN
 
 
_InitArray                             ' Init example array
  PUSH 4, 65, 2, -31, 0, 99, 2, 83, 782, 1
 
  FOR i = 0 TO 9
    @(i) = POP()
  NEXT
 
RETURN (i)
 
 
_ShowArray PARAM (1)                   ' Show array subroutine
  FOR i = 0 TO a@-1
    PRINT @(i),
  NEXT
 
  PRINT
RETURN

Wren[edit]

var stoogeSort // recursive
stoogeSort = Fn.new { |a, i, j|
    if (a[j] < a[i]) {
        var t = a[i]
        a[i] = a[j]
        a[j] = t
    }
    if (j - i > 1) {
        var t = ((j - i + 1)/3).floor
        stoogeSort.call(a, i, j - t)
        stoogeSort.call(a, i + t, j)
        stoogeSort.call(a, i, j - t)
    }
}

var as = [ [4, 65, 2, -31, 0, 99, 2, 83, 782, 1], [7, 5, 2, 6, 1, 4, 2, 6, 3] ]
for (a in as) {
    System.print("Before: %(a)")
    stoogeSort.call(a, 0, a.count-1)
    System.print("After : %(a)")
    System.print()
}
Output:
Before: [4, 65, 2, -31, 0, 99, 2, 83, 782, 1]
After : [-31, 0, 1, 2, 2, 4, 65, 83, 99, 782]

Before: [7, 5, 2, 6, 1, 4, 2, 6, 3]
After : [1, 2, 2, 3, 4, 5, 6, 6, 7]

XPL0[edit]

code ChOut=8, IntOut=11;        \intrinsic routines

proc StoogeSort(L, I, J);       \Sort array L
int L, I, J;
int  T;
[if L(J) < L(I) then
    [T:= L(I);  L(I):= L(J);  L(J):= T]; \swap
if J-I > 1 then
    [T:= (J-I+1)/3;
    StoogeSort(L, I, J-T);
    StoogeSort(L, I+T, J);
    StoogeSort(L, I, J-T);
    ];
];

int A, I;
[A:= [3, 1, 4, 1, -5, 9, 2, 6, 5, 4];
StoogeSort(A, 0, 10-1);
for I:= 0 to 10-1 do [IntOut(0, A(I));  ChOut(0, ^ )];
]
Output:
-5 1 1 2 3 4 4 5 6 9 

Yorick[edit]

Based on pseudocode, except using Yorick's 1-based arrays. Sorts in place.

func stoogesort(&L, i, j) {
  if(is_void(i)) i = 1;
  if(is_void(j)) j = numberof(L);
  if(L(j) < L(i))
    L([i,j]) = L([j,i]);
  if(j - i > 1) {
    t = (j - i + 1)/3;
    stoogesort, L, i, j-t;
    stoogesort, L, i+t, j;
    stoogesort, L, i, j-t;
  }
}

Example interactive use:

> foo = [1,4,5,3,-6,3,7,10,-2,-5]
> stoogesort, foo
> foo
[-6,-5,-2,1,3,3,4,5,7,10]

zkl[edit]

fcn stoogeSort(list,i=0,j=Void){ if(Void==j) j=list.len() - 1; // default parameters set before call
   if(list[j]<list[i]) list.swap(i,j);
   if(j - i >1){
      t:=(j - i + 1)/3;
      stoogeSort(list,i  , j-t);
      stoogeSort(list,i+t, j  );
      stoogeSort(list,i  , j-t);
   }
   list
}
stoogeSort(List(67,-201,0,9,9,231,4)).println();
Output:
L(-201,0,4,9,9,67,231)