Python Program for Heap Sort
Heap sort is a comparison based sorting technique based on Binary Heap data structure. It is similar to selection sort where we first find the maximum element and place the maximum element at the end. We repeat the same process for remaining element.
# Python program for implementation of heap Sort # To heapify subtree rooted at index i. # n is size of heap def heapify(arr, n, i): largest = i # Initialize largest as root l = 2 * i + 1 # left = 2*i + 1 r = 2 * i + 2 # right = 2*i + 2 # See if left child of root exists and is # greater than root if l < n and arr[i] < arr[l]: largest = l # See if right child of root exists and is # greater than root if r < n and arr[largest] < arr[r]: largest = r # Change root, if needed if largest != i: arr[i],arr[largest] = arr[largest],arr[i] # swap # Heapify the root. heapify(arr, n, largest) # The main function to sort an array of given size def heapSort(arr): n = len(arr) # Build a maxheap. for i in range(n, -1, -1): heapify(arr, n, i) # One by one extract elements for i in range(n-1, 0, -1): arr[i], arr[0] = arr[0], arr[i] # swap heapify(arr, i, 0) # Driver code to test above arr = [ 12, 11, 13, 5, 6, 7] heapSort(arr) n = len(arr) print ("Sorted array is") for i in range(n): print ("%d" %arr[i]), # |
Output:
Sorted array is 5 6 7 11 12 13