// C++ implementation of Shell Sort
#include  <iostream>
using namespace std;
 
/* function to sort arr using shellSort */
int shellSort(int arr[], int n)
{
    // Start with a big gap, then reduce the gap
    for (int gap = n/2; gap > 0; gap /= 2)
    {
        // Do a gapped insertion sort for this gap size.
        // The first gap elements a[0..gap-1] are already in gapped order
        // keep adding one more element until the entire array is
        // gap sorted 
        for (int i = gap; i < n; i += 1)
        {
            // add a[i] to the elements that have been gap sorted
            // save a[i] in temp and make a hole at position i
            int temp = arr[i];
 
            // shift earlier gap-sorted elements up until the correct 
            // location for a[i] is found
            int j;            
            for (j = i; j >= gap && arr[j - gap] > temp; j -= gap)
                arr[j] = arr[j - gap];
             
            //  put temp (the original a[i]) in its correct location
            arr[j] = temp;
        }
    }
    return 0;
}
 
void printArray(int arr[], int n)
{
    for (int i=0; i<n; i++)
        cout << arr[i] << " ";
}
 
int main()
{
    int arr[] = {12, 34, 54, 2, 3}, i;
    int n = sizeof(arr)/sizeof(arr[0]);
 
    cout << "Array before sorting: \n";
    printArray(arr, n);
 
    shellSort(arr, n);
 
    cout << "\nArray after sorting: \n";
    printArray(arr, n);
 
    return 0;
}

// Java implementation of ShellSort
class ShellSort
{
    /* An utility function to print array of size n*/
    static void printArray(int arr[])
    {
        int n = arr.length;
        for (int i=0; i<n; ++i)
            System.out.print(arr[i] + " ");
        System.out.println();
    }
 
    /* function to sort arr using shellSort */
    int sort(int arr[])
    {
        int n = arr.length;
 
        // Start with a big gap, then reduce the gap
        for (int gap = n/2; gap > 0; gap /= 2)
        {
            // Do a gapped insertion sort for this gap size.
            // The first gap elements a[0..gap-1] are already
            // in gapped order keep adding one more element
            // until the entire array is gap sorted
            for (int i = gap; i < n; i += 1)
            {
                // add a[i] to the elements that have been gap
                // sorted save a[i] in temp and make a hole at
                // position i
                int temp = arr[i];
 
                // shift earlier gap-sorted elements up until
                // the correct location for a[i] is found
                int j;
                for (j = i; j >= gap && arr[j - gap] > temp; j -= gap)
                    arr[j] = arr[j - gap];
 
                // put temp (the original a[i]) in its correct
                // location
                arr[j] = temp;
            }
        }
        return 0;
    }
 
    // Driver method
    public static void main(String args[])
    {
        int arr[] = {12, 34, 54, 2, 3};
        System.out.println("Array before sorting");
        printArray(arr);
 
        ShellSort ob = new ShellSort();
        ob.sort(arr);
 
        System.out.println("Array after sorting");
        printArray(arr);
    }
} 

# Python program for implementation of Shell Sort
 
def shellSort(arr):
 
    # Start with a big gap, then reduce the gap
    n = len(arr)
    gap = n/2
 
    # Do a gapped insertion sort for this gap size.
    # The first gap elements a[0..gap-1] are already in gapped 
    # order keep adding one more element until the entire array
    # is gap sorted
    while gap > 0:
 
        for i in range(gap,n):
 
            # add a[i] to the elements that have been gap sorted
            # save a[i] in temp and make a hole at position i
            temp = arr[i]
 
            # shift earlier gap-sorted elements up until the correct
            # location for a[i] is found
            j = i
            while  j >= gap and arr[j-gap] >temp:
                arr[j] = arr[j-gap]
                j -= gap
 
            # put temp (the original a[i]) in its correct location
            arr[j] = temp
        gap /= 2
 
 
# Driver code to test above
arr = [ 12, 34, 54, 2, 3]
 
n = len(arr)
print ("Array before sorting:")
for i in range(n):
    print(arr[i]),
 
shellSort(arr)
 
print ("\nArray after sorting:")
for i in range(n):
    print(arr[i]),