added merge sort problem

MergeSort.py

@@ -0,0 +1,61 @@
+'''
+Problem Statement : Sort a list using merge sort algorithm
+'''
+
+
+
+# funtion to divide the lists in the two sublists
+def merge_sort(list1, left_index, right_index):
+    if left_index >= right_index:
+        return
+
+    middle = (left_index + right_index) // 2
+    merge_sort(list1, left_index, middle)
+    merge_sort(list1, middle + 1, right_index)
+    merge(list1, left_index, right_index, middle)
+
+    # Defining a function for merge the list
+
+
+def merge(list1, left_index, right_index, middle):
+    # Creating subparts of a lists
+    left_sublist = list1[left_index:middle + 1]
+    right_sublist = list1[middle + 1:right_index + 1]
+
+    # Initial values for variables that we use to keep
+    # track of where we are in each list1
+    left_sublist_index = 0
+    right_sublist_index = 0
+    sorted_index = left_index
+
+    # traverse both copies until we get run out one element
+    while left_sublist_index < len(left_sublist) and right_sublist_index < len(right_sublist):
+
+        # If our left_sublist has the smaller element, put it in the sorted
+        # part and then move forward in left_sublist (by increasing the pointer)
+        if left_sublist[left_sublist_index] <= right_sublist[right_sublist_index]:
+            list1[sorted_index] = left_sublist[left_sublist_index]
+            left_sublist_index = left_sublist_index + 1
+            # Otherwise add it into the right sublist
+        else:
+            list1[sorted_index] = right_sublist[right_sublist_index]
+            right_sublist_index = right_sublist_index + 1
+
+            # move forward in the sorted part
+        sorted_index = sorted_index + 1
+
+        # we will go through the remaining elements and add them
+    while left_sublist_index < len(left_sublist):
+        list1[sorted_index] = left_sublist[left_sublist_index]
+        left_sublist_index = left_sublist_index + 1
+        sorted_index = sorted_index + 1
+
+    while right_sublist_index < len(right_sublist):
+        list1[sorted_index] = right_sublist[right_sublist_index]
+        right_sublist_index = right_sublist_index + 1
+        sorted_index = sorted_index + 1
+
+
+list1 = [44, 65, 2, 3, 58, 14, 57, 23, 10, 1, 7, 74, 48]
+merge_sort(list1, 0, len(list1) - 1)
+print(list1)