Add files via upload (hacktoberfest17#1156)

Author: pyjka

sorting/Coctail_sort.py

@@ -0,0 +1,13 @@
+def coctailsort(arr):
+    for i in range(len(arr) - 1, 0, -1):
+        swapped = False
+        for j in range(i, 0, -1):
+            if arr[j] < arr[j - 1]:
+                arr[j], arr[j - 1] = arr[j - 1], arr[j]
+                swapped = True
+        for i in range(i):
+            if arr[i] > arr[i + 1]:
+                arr[i], arr[i + 1] = arr[i + 1], arr[i]
+                swapped = True
+        if not swapped:
+            return arr