Adding heap sort code which I found online; edited and gave credit to the author(s), and heap.py

heap.py

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+# Luis Andrés López Mañán
+# Program written by hand as a draft on 09/19/2022
+# Credit goes to GeeksForGeeks
+# Link: https://www.geeksforgeeks.org/python-program-for-heap-sort/
+# Last access on 09/19/2022
+# Program wrriten and edited on 10/10/2022
+
+# This function heapifies a subtree rooted at an index
+# i. Also, n is the size of a heap and arr is array.
+
+def heapify (arr, n, i):
+		# largest is root for now
+		largest = i
+		
+		# left child of root
+		left = 2 * i + 1
+		
+		# right child of root
+		right = 2 * i + 2
+		
+		# Checks if root has a left child and is greater
+		# than root
+		if l < n and arr[i] < arr[l] :
+			largest = l
+			
+		# Checks if root has a right child and is greater
+		# than root
+		if r < n and arr[largest] < arr[r]:
+			largest = r
+			
+		# If necessary, this changes root by swapping va-
+		# lues
+		arr[i], arr[largest] = arr[largest], arr[i]
+		
+		# This heapifies the root repeatedly
+		heapify(arr, n, largest)
+		
+# This function sorts an array of a given size n
+def heapSort(arr, n):
+		# A max heap is built and last parent will be at
+		# position number h1, i.e., half the given size of
+		# and array. Therefore, that will be the starting
+		# location.
+		h1 = n // 2 - 1
+		for i in range(h1, -1, -1):
+			heapify(arr, n, i)
+			
+		# This extracts elements one by one.
+		for i in range(n - 1, 0, -1):
+			# Swaps, then heapifies
+			arr[i], arr[0] = arr[0], arr[i]
+			heapify(arr, i, 0)
+