diff --git a/heap.py b/heap.py new file mode 100644 index 0000000..8680137 --- /dev/null +++ b/heap.py @@ -0,0 +1,47 @@ +# 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]), +# This code is contributed by Mohit Kumra