Java Program for Stooge Sort

The Stooge sort is a recursive sorting algorithm. It is defined as below (for ascending order sorting).

Step 1 : If value at index 0 is greater than
         value at last index, swap them.
Step 2:  Recursively,
       a) Stooge sort the initial 2/3rd of the array.
       b) Stooge sort the last 2/3rd of the array.
       c) Stooge sort the initial 2/3rd again to confirm.

Java

// Java program to implement stooge sort
import java.io.*;

public class stooge
{
 // Function to implement stooge sort
 static void stoogesort(int arr[], int l, int h)
 {
  if (l >= h)
  return;

  // If first element is smaller
  // than last,swap them
  if (arr[l] > arr[h])
  {
   int t = arr[l];
   arr[l] = arr[h];
   arr[h] = t;
  }

  // If there are more than 2 elements in
  // the array
  if (h-l+1 > 2)
  {
   int t = (h-l+1) / 3;

   // Recursively sort first 2/3 elements
   stoogesort(arr, l, h-t);

   // Recursively sort last 2/3 elements
   stoogesort(arr, l+t, h);

   // Recursively sort first 2/3 elements
   // again to confirm
   stoogesort(arr, l, h-t);
  }
 }

 // Driver Code
 public static void main(String args[])
 {
  int arr[] = {2, 4, 5, 3, 1};
  int n = arr.length;

  stoogesort(arr, 0, n-1);

  for (int i=0; i < n; i++)
   System.out.print(arr[i] + " ");
 }
}
// Code Contributed by Mohit Gupta_OMG <(0_o)>

Output:

1 2 3 4 5 

Time Complexity:
The running time complexity of stooge sort can be written as,
T(n) = 3T(3n/2) + O(1)
Solution of above recurrence is O(n(log3/log1.5)) = O(n^2.709), hence it is slower than even bubble sort(n²).
Auxiliary Space: O(n)

Please refer complete article on Stooge Sort for more details!