# Write a Python Program for ShellSort # 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 abovearr = [ 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]),  # This code is contributed by Mohit Kumra