Added implementations of gnome sort and cocktail shaker sort

sorts/cocktail_shaker_sort.py

@@ -0,0 +1,36 @@
+from __future__ import print_function
+
+def cocktail_shaker_sort(unsorted):
+    """
+    Pure implementation of the cocktail shaker sort algorithm in Python.
+    """
+    for i in range(len(unsorted)-1, 0, -1):
+        swapped = False
+        
+        for j in range(i, 0, -1):
+            if unsorted[j] < unsorted[j-1]:
+                unsorted[j], unsorted[j-1] = unsorted[j-1], unsorted[j]
+                swapped = True
+
+        for j in range(i):
+            if unsorted[j] > unsorted[j+1]:
+                unsorted[j], unsorted[j+1] = unsorted[j+1], unsorted[j]
+                swapped = True
+        
+        if not swapped:
+            return unsorted
+            
+if __name__ == '__main__':
+    import sys
+
+    # For python 2.x and 3.x compatibility: 3.x has not raw_input builtin
+    # otherwise 2.x's input builtin function is too "smart"
+    if sys.version_info.major < 3:
+        input_function = raw_input
+    else:
+        input_function = input
+    
+    user_input = input_function('Enter numbers separated by a comma:\n')
+    unsorted = [int(item) for item in user_input.split(',')]
+    cocktail_shaker_sort(unsorted)
+    print(unsorted)

sorts/gnome_sort.py

@@ -0,0 +1,34 @@
+from __future__ import print_function
+
+def gnome_sort(unsorted):
+    """
+    Pure implementation of the gnome sort algorithm in Python.
+    """
+    if len(unsorted) <= 1:
+        return unsorted
+        
+    i = 1
+    
+    while i < len(unsorted):
+        if unsorted[i-1] <= unsorted[i]:
+            i += 1
+        else:
+            unsorted[i-1], unsorted[i] = unsorted[i], unsorted[i-1]
+            i -= 1
+            if (i == 0):
+                i = 1
+                
+if __name__ == '__main__':
+    import sys
+
+    # For python 2.x and 3.x compatibility: 3.x has not raw_input builtin
+    # otherwise 2.x's input builtin function is too "smart"
+    if sys.version_info.major < 3:
+        input_function = raw_input
+    else:
+        input_function = input
+    
+    user_input = input_function('Enter numbers separated by a comma:\n')
+    unsorted = [int(item) for item in user_input.split(',')]
+    gnome_sort(unsorted)
+    print(unsorted)