Python Program for ShellSort
In shellSort, we make the array h-sorted for a large value of h. We keep reducing the value of h until it becomes 1. An array is said to be h-sorted if all sublists of every h\’th element is sorted.
# 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]), # |
Output:
Array before sorting: 12 34 54 2 3 Array after sorting: 2 3 12 34 54