Sorting algorithms/Stooge sort

Sorting algorithms/Stooge sort
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Sorting Algorithm
This is a sorting algorithm.   It may be applied to a set of data in order to sort it.     For comparing various sorts, see compare sorts.   For other sorting algorithms,   see sorting algorithms,   or:

O(n logn) sorts

Heap sort | Merge sort | Patience sort | Quick sort

O(n log²n) sorts
Shell Sort

O(n²) sorts
Bubble sort | Cocktail sort | Cocktail sort with shifting bounds | Comb sort | Cycle sort | Gnome sort | Insertion sort | Selection sort | Strand sort

other sorts
Bead sort | Bogo sort | Common sorted list | Composite structures sort | Custom comparator sort | Counting sort | Disjoint sublist sort | External sort | Jort sort | Lexicographical sort | Natural sorting | Order by pair comparisons | Order disjoint list items | Order two numerical lists | Object identifier (OID) sort | Pancake sort | Quickselect | Permutation sort | Radix sort | Ranking methods | Remove duplicate elements | Sleep sort | Stooge sort | [Sort letters of a string] | Three variable sort | Topological sort | Tree sort

This page uses content from Wikipedia. The original article was at Sorting algorithms/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)

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

D

<lang d>import std.stdio ;

T[] stooge(T)(ref T[] l) {

   if(l[$-1] < l[0]) {
       T t = l[0] ;
       l[0] = l[$-1] ;
       l[$-1] = t ;
   }
   if(l.length > 2) {
       T[] r ;
       int m = l.length  / 3 ;
       r = l[0..$ - m] ; stooge(r) ;
       r = l[m..$]     ; stooge(r) ;
       r = l[0..$ - m] ; stooge(r) ;
   }
   return l ;

}

void main() {

   auto num = [1, 4, 5, 3, -6, 3, 7, 10, -2, -5] ;

   writefln("%s", num.stooge) ;

}</lang>

Haskell

<lang haskell>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</lang> Example: <lang haskell>*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]</lang>

Java

<lang java>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);
       }
   }

}</lang> Output:

[-6, -5, -2, 1, 3, 3, 4, 5, 7, 10]

Oz

<lang oz>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</lang>

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,

PureBasic

<lang PureBasic>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</lang> Implementation may be as<lang PureBasic>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</lang>

Python

<lang python>>>> 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]</lang>

This alternate solution uses a wrapper function to compute the initial value of j rather than detecting the sentinel value None. <lang python>>>> 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]</lang>

Tcl

Works with: Tcl version 8.5

<lang tcl>package require Tcl 8.5

proc stoogesort { L {i 0} {j ""} } {

  if {$j==""} {
     set j [expr [llength $L]-1]
  }
  set Li [lindex $L $i]
  set Lj [lindex $L $j]
  if {$Lj < $Li } {
     set L [lreplace $L $i $i $Lj]
     set L [lreplace $L $j $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}

</lang> Output:

-6 -5 -2 1 3 3 4 5 7 10