Stooge Sort is a recursive sorting algorithm. It is not much efficient but interesting sorting algorithm. It generally divides the array into two overlapping parts (2/3 each). After that it performs sorting in first 2/3 part and then it performs sorting in last 2/3 part. And then, sorting is done on first 2/3 part to ensure that the array is sorted.
The key idea is that sorting the overlapping part twice exchanges the elements between the other two sections accordingly.
Approach:
Step 1: If value at index 0 is greater than value at last index, swap them.
Step 2: Recursively,
- Stooge sort the initial 2/3rd of the array.
- Stooge sort the last 2/3rd of the array.
- Stooge sort the initial 2/3rd again to confirm.
NOTE: Always take the ceil of ((2/3)*N) for selecting elements.
Illustration:
Lets consider an example: arr[] = {2, 4, 5, 3, 1}
- Step1: Initially, First and last elements are compared and if last is greater than first then they are swapped.
1 4 5 3 2
- Step2: Now, recursively sort initial 2/3rd of the elements as shown below:
1 4 5 3 2
1 3 4 5 2
- Step3: Then, recursively sort last 2/3rd of the elements, as shown below:
1 3 4 5 2
1 2 3 4 5
- Step4: Again, sort the initial 2/3rd of the elements to confirm final data is sorted.
- Resulted array:
1 2 3 4 5
Below is the implementation for the above approach:
// C++ code to implement stooge sort #include <iostream> using namespace std;
// Function to implement stooge sort 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])
swap(arr[l], arr[h]);
// 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 int main()
{ int arr[] = { 2, 4, 5, 3, 1 };
int n = sizeof (arr) / sizeof (arr[0]);
// Calling Stooge Sort function to sort
// the array
stoogesort(arr, 0, n - 1);
// Display the sorted array
for ( int i = 0; i < n; i++)
cout << arr[i] << " " ;
return 0;
} |
// 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)> |
# 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))
# deriver 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)> |
// C# program to implement stooge sort using System;
class GFG {
// 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()
{
int [] arr = { 2, 4, 5, 3, 1 };
int n = arr.Length;
// Calling Stooge Sort function
// to sort the array
stoogesort(arr, 0, n - 1);
// Display the sorted array
for ( int i = 0; i < n; i++)
Console.Write(arr[i] + " " );
}
} // This code is contributed by Sam007. |
<script> // Javascript program to implement stooge sort
// Function to implement stooge sort
function stoogesort(arr, l, h)
{
if (l >= h)
return ;
// If first element is smaller
// than last, swap them
if (arr[l] > arr[h]) {
let 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) {
let t = parseInt((h - l + 1) / 3, 10);
// 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);
}
}
let arr = [ 2, 4, 5, 3, 1 ];
let n = arr.length;
// Calling Stooge Sort function
// to sort the array
stoogesort(arr, 0, n - 1);
// Display the sorted array
for (let i = 0; i < n; i++)
document.write(arr[i] + " " );
</script> |
1 2 3 4 5
The running time complexity of stooge sort can be written as,
T(n) = 3T(2n/3) + ?(1)
Solution of above recurrence is O(n(log3/log1.5)) = O(n2.709), hence it is slower than even bubble sort(n^2).