Create heap_sort.py

Algorithms/sorting/heap_sort.py

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+# 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) 
+
+def heapSort(arr): 
+	n = len(arr) 
+
+	# Build a maxheap - since last parent will be at ((n//2)-1) we can start at that location. 
+	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) 
+
+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]), 

Algorithms/sorting/selection_sort.py

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+import sys 
+A = [100, 50, 200, 60, 40] 
+
+# Traverse through all array elements 
+for i in range(len(A)): 
+
+    # Find the minimum element in remaining unsorted array 
+    min_idx = i 
+    for j in range(i+1, len(A)): 
+        if A[min_idx] > A[j]: 
+            min_idx = j 
+
+    # Swap the found minimum element with the first element         
+    A[i], A[min_idx] = A[min_idx], A[i] 
+
+print ("Sorted array") 
+for i in range(len(A)): 
+    print("%d" %A[i]),