Create cocktail_shaker_sort and add test case (keon#310)

* Create cocktail_shaker_sort.py

* Update __init__.py

* Update test_sort.py

* Update test_sort.py

* Update README.md

* Update README_CN.md

* Update README_CN.md

* Update README.md

* Update README_GE.md

* Update README_JP.md

* Update README_KR.md

Author: hsi1032

README.md

@@ -225,6 +225,7 @@ If you want to uninstall algorithms, it is as simple as:
     - [bogo_sort](algorithms/sort/bogo_sort.py)
     - [bubble_sort](algorithms/sort/bubble_sort.py)
     - [bucket_sort](algorithms/sort/bucket_sort.py)
+    - [cocktail_shaker_sort](algorithms/sort/cocktail_shaker_sort.py)
     - [comb_sort](algorithms/sort/comb_sort.py)
     - [counting_sort](algorithms/sort/counting_sort.py)
     - [heap_sort](algorithms/sort/heap_sort.py)

README_CN.md

@@ -209,6 +209,7 @@ pip3 uninstall -y algorithms
     - [bogo_sort](algorithms/sort/bogo_sort.py)
     - [bubble_sort：冒泡排序](algorithms/sort/bubble_sort.py)
     - [bucket_sort](algorithms/sort/bucket_sort.py)
+    - [cocktail_shaker_sort](algorithms/sort/cocktail_shaker_sort.py)
     - [comb_sort：梳排序](algorithms/sort/comb_sort.py)
     - [counting_sort：计数排序](algorithms/sort/counting_sort.py)
     - [heap_sort：堆排序](algorithms/sort/heap_sort.py)

README_GE.md

@@ -230,6 +230,7 @@ Um das Projekt zu deinstallieren tippen Sie folgendes:
     - [bogo_sort](algorithms/sort/bogo_sort.py)
     - [bubble_sort](algorithms/sort/bubble_sort.py)
     - [bucket_sort](algorithms/sort/bucket_sort.py)
+    - [cocktail_shaker_sort](algorithms/sort/cocktail_shaker_sort.py)
     - [comb_sort](algorithms/sort/comb_sort.py)
     - [counting_sort](algorithms/sort/counting_sort.py)
     - [heap_sort](algorithms/sort/heap_sort.py)

README_JP.md

@@ -224,6 +224,7 @@ if __name__ == "__main__":
     - [bogo_sort](algorithms/sort/bogo_sort.py)
     - [bubble_sort](algorithms/sort/bubble_sort.py)
     - [bucket_sort](algorithms/sort/bucket_sort.py)
+    - [cocktail_shaker_sort](algorithms/sort/cocktail_shaker_sort.py)
     - [comb_sort](algorithms/sort/comb_sort.py)
     - [counting_sort](algorithms/sort/counting_sort.py)
     - [heap_sort](algorithms/sort/heap_sort.py)

README_KR.md

@@ -220,6 +220,7 @@ if __name__ == "__main__":
 - [sort : 정렬 알고리즘](algorithms/sort)
     - [bogo_sort](algorithms/sort/bogo_sort.py)
     - [bubble_sort](algorithms/sort/bubble_sort.py)
+    - [cocktail_shaker_sort](algorithms/sort/cocktail_shaker_sort.py)
     - [comb_sort](algorithms/sort/comb_sort.py)
     - [counting_sort](algorithms/sort/counting_sort.py)
     - [heap_sort](algorithms/sort/heap_sort.py)

algorithms/sort/__init__.py

@@ -11,3 +11,4 @@
 from .bucket_sort import *
 from .shell_sort import *
 from .radix_sort import *
+from .cocktail_shaker_sort import *

algorithms/sort/cocktail_shaker_sort.py

@@ -0,0 +1,30 @@
+def cocktail_shaker_sort(arr):
+    """
+    Cocktail_shaker_sort
+    Sorting a given array
+    mutation of bubble sort
+
+    reference: https://en.wikipedia.org/wiki/Cocktail_shaker_sort
+    
+    Worst-case performance: O(N^2)
+    """
+
+    def swap(i, j):
+        arr[i], arr[j] = arr[j], arr[i]
+
+    n = len(arr)
+    swapped = True
+    while swapped:
+        swapped = False
+        for i in range(1, n):
+            if arr[i - 1] > arr[i]:
+                swap(i - 1, i)
+                swapped = True
+        if swapped == False:
+            return arr
+        swapped = False
+        for i in range(n-1,0,-1):
+            if arr[i - 1] > arr[i]:
+                swap(i - 1, i)
+                swapped = True
+    return arr

tests/test_sort.py

@@ -10,7 +10,8 @@
     selection_sort,
     bucket_sort,
     shell_sort,
-    radix_sort
+    radix_sort,
+    cocktail_shaker_sort
 )
 
 import unittest
@@ -68,7 +69,10 @@ def test_shell_sort(self):
     def test_radix_sort(self):
         self.assertEqual([1, 5, 23, 57, 65, 1232],
                         radix_sort([1, 5, 65, 23, 57, 1232]))
-                                          
+     
+    def test_cocktail_shaker_sort(self):
+        self.assertEqual([1, 5, 23, 57, 65, 1232],
+                        cocktail_shaker_sort([1, 5, 65, 23, 57, 1232]))
 
 
 if __name__ == "__main__":