Update sorting.py by adding heap sort´s code

sorting.py

@@ -9,12 +9,33 @@ Al final se imprimen los promedios de cada algortimo
 from random import randint
 import time
 from merge import merge
-import heapq
+import heapify # Se importa esa librería para usar heapify
 
-def mergeSort(lista):
-	#definan el algoritmo de ordenamiento mergesort
-	return lista
+'''
+ Python program for implementation of MergeSort  taken from https://www.geeksforgeeks.org/python-program-for-merge-sort/#:~:text=Merge%20Sort%20is%20a%20Divide,assumes%20that%20arr%5Bl..
+ Merges two subarrays of arr[].
+ First subarray is arr[l..m]
+ Second subarray is arr[m+1..r]
+'''
+
+
+def mergeSort(lista, l, r):
+	if l < r:
+		# Same as (l+r)//2, but avoids overflow for
+		# large l and h
+		m = l + (r - l) // 2
+
+		# Sort first and second halves
+		mergeSort(lista, l, m)
+		mergeSort(lista, m + 1, r)
+		merge(lista, l, m, r)
 
+""" Código tomado de GeeksForGeeks.
+	Enlace electrónico del código 
+ 	encontrado y adaptado para la
+  	asignación o el proyecto de prác-
+   	tica con git: https://www.geeksforgeeks.org/heap-sort/
+"""
 def heapSort(lista):
 	#definan el algoritmo de ordenamiento heapsort
 	heapq.heapify(lista)
@@ -42,8 +63,33 @@ def quickSort(lista):
 	#definan el algoritmo de ordenamiento quicksort
 	return lista
 
+
+''' 
+	This algorithm was taken from: https://www.programiz.com/dsa/shell-sort 
+	and was adapted in order to work for this assigment.
+'''
+
+
 def shellSort(lista):
-	#definan el algoritmo de ordenamiento shellsort
+	# Determine the list size to find the gap.
+	n = len(lista)
+	gap = n // 2
+
+	# this algorithm will run until gap reaches 1
+	while gap > 0:
+		for i in range(gap, n):
+			temp = lista[i]  # storing all items from lista into temp
+			j = i
+
+			# compares the number in temp with the 0th possition (start of list)
+			# if temp is larger than the first element then we swap them
+			while j >= gap and lista[j - gap] > temp:
+				lista[j] = lista[j - gap]
+				j -= gap
+
+			lista[j] = temp
+		gap = gap // 2  # decreases the gap to continue the loop
+
 	return lista
 
 maxValor=1000 	#define el valor maximo de los elementos de la lista