Merge pull request ephremdeme#65 from shaswatsingh19/master

heap sort

Author: ephremdeme

sorting-algorithms/Heap Sort.py

@@ -0,0 +1,40 @@
+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) 
+
+def heapSort(arr): 
+n = len(arr) 
+
+# Build a maxheap. 
+for i in range(n//2 - 1, -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) 
+
+print('Enter a list of numbers')
+arr = list(map(int,input().split()))
+heapSort(arr) 
+print('After performing heap sort')
+for i in arr:
+ print(i,end =' ')