JeLuOrRi/heap.py

''' 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(lista, n, i):
        # largest is root for now
		largest = i

		# left child of root
		l = 2 * i + 1

		# right child of root
		r = 2 * i + 2

		# Checks if root has a left child and is greater
		# than root
		if l < n and lista[i] < lista[l] :
			largest = l

		# Checks if root has a right child and is greater
		# than root
		if r < n and lista[largest] < lista[r]:
			largest = r

		# If necessary, this changes root by swapping va-
		# lues
        if largest != i:
            lista[i], lista[largest] = lista[largest], lista[i]

		# This heapifies the root repeatedly
		heapify(lista, n, largest)