Added merge sort

Patterns/factorial.py

@@ -0,0 +1,15 @@
+
+print "Enter a number to get factorial."
+userInput = map(int, raw_input().split())
+
+i = 1
+answer = 1
+if(userInput[0] != 0):
+	while(i <= userInput[0]):
+
+		tmp = answer
+		answer = i * tmp
+		i = i + 1
+
+print answer
+

SortingAlgorithms/merge_sort.py

@@ -0,0 +1,38 @@
+
+def mergeSort(listToSort):
+	if(len(listToSort) > 1):
+		mid = len(listToSort)//2
+		lower = listToSort[:mid]
+		upper = listToSort[mid:]
+
+		mergeSort(lower)
+		mergeSort(upper)
+
+		i = 0
+		j = 0
+		k = 0
+		while(i < len(lower) and j < len(upper)):
+			if(lower[i] < upper[j]):
+				listToSort[k] = lower[i]
+				i = i + 1
+			else:
+				listToSort[k] = upper[j]
+				j = j + 1
+			k = k + 1
+
+		while(i < len(lower)):
+			listToSort[k] = lower[i]
+			i = i + 1
+			k = k + 1
+
+		while(j < len(upper)):
+			listToSort[k] = upper[j]
+			j = j + 1
+			k = k + 1
+
+print "Enter numbers to be sorted (separated by space)"
+
+userList = map(int, raw_input().split())
+mergeSort(userList)
+
+print userList