Update cocktail_shaker_sort.py (#10987)

* Update cocktail_shaker_sort.py

Added a docstring with clear explanations of the function and its parameters.

Changed variable names i, start, and end for better readability.

Improved comments to describe the purpose of each section of the algorithm.

Adjusted the loop ranges to make the code more concise and readable.

Removed redundant comments and variable assignments.

Provided a clear message when printing the sorted list.

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Update cocktail_shaker_sort.py

* typing: ignore[operator]

* Update cocktail_shaker_sort.py

* Update cocktail_shaker_sort.py

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Christian Clauss <cclauss@me.com>

Author: 3 people

sorts/cocktail_shaker_sort.py

@@ -1,40 +1,62 @@
-""" https://en.wikipedia.org/wiki/Cocktail_shaker_sort """
+"""
+An implementation of the cocktail shaker sort algorithm in pure Python.
 
+https://en.wikipedia.org/wiki/Cocktail_shaker_sort
+"""
 
-def cocktail_shaker_sort(unsorted: list) -> list:
+
+def cocktail_shaker_sort(arr: list[int]) -> list[int]:
     """
-    Pure implementation of the cocktail shaker sort algorithm in Python.
+    Sorts a list using the Cocktail Shaker Sort algorithm.
+
+    :param arr: List of elements to be sorted.
+    :return: Sorted list.
+
     >>> cocktail_shaker_sort([4, 5, 2, 1, 2])
     [1, 2, 2, 4, 5]
-
     >>> cocktail_shaker_sort([-4, 5, 0, 1, 2, 11])
     [-4, 0, 1, 2, 5, 11]
-
     >>> cocktail_shaker_sort([0.1, -2.4, 4.4, 2.2])
     [-2.4, 0.1, 2.2, 4.4]
-
     >>> cocktail_shaker_sort([1, 2, 3, 4, 5])
     [1, 2, 3, 4, 5]
-
     >>> cocktail_shaker_sort([-4, -5, -24, -7, -11])
     [-24, -11, -7, -5, -4]
+    >>> cocktail_shaker_sort(["elderberry", "banana", "date", "apple", "cherry"])
+    ['apple', 'banana', 'cherry', 'date', 'elderberry']
+    >>> cocktail_shaker_sort((-4, -5, -24, -7, -11))
+    Traceback (most recent call last):
+        ...
+    TypeError: 'tuple' object does not support item assignment
     """
-    for i in range(len(unsorted) - 1, 0, -1):
+    start, end = 0, len(arr) - 1
+
+    while start < end:
         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]
+        # Pass from left to right
+        for i in range(start, end):
+            if arr[i] > arr[i + 1]:
+                arr[i], arr[i + 1] = arr[i + 1], arr[i]
                 swapped = True
 
-        for j in range(i):
-            if unsorted[j] > unsorted[j + 1]:
-                unsorted[j], unsorted[j + 1] = unsorted[j + 1], unsorted[j]
+        if not swapped:
+            break
+
+        end -= 1  # Decrease the end pointer after each pass
+
+        # Pass from right to left
+        for i in range(end, start, -1):
+            if arr[i] < arr[i - 1]:
+                arr[i], arr[i - 1] = arr[i - 1], arr[i]
                 swapped = True
 
         if not swapped:
             break
-    return unsorted
+
+        start += 1  # Increase the start pointer after each pass
+
+    return arr
 
 
 if __name__ == "__main__":