Python 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.

Python3

# Python program to implement stooge sort

def stoogesort(arr, l, h):
 if l >= h:
  return

 # If first element is smaller
 # than last,swap them
 if arr[l]>arr[h]:
  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:
  t = (int)((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
arr = [2, 4, 5, 3, 1]
n = len(arr)

stoogesort(arr, 0, n-1)

for i in range(0, n):
 print(arr[i], end = ' ')

# 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!