bubble sort recursion (#30)

* bubble sort recursion

* Formatted with psf/black

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>

Author: realDuYuanChao

sorts/bubble_sort_recursion.py

@@ -0,0 +1,38 @@
+"""
+https://en.wikipedia.org/wiki/Bubble_sort
+"""
+
+
+def bubble_sort(array, length: int = 0):
+    """
+    :param array: the array to be sorted.
+    :param length: the length of array.
+    :return: sorted array.
+    >>> import random
+    >>> array = random.sample(range(-50, 50), 100)
+    >>> bubble_sort(array) == sorted(array)
+    True
+    >>> import string
+    >>> array = random.choices(string.ascii_letters + string.digits, k = 100)
+    >>> bubble_sort(array) == sorted(array)
+    True
+    >>> array = [random.uniform(-50.0, 50.0) for i in range(100)]
+    >>> bubble_sort(array) == sorted(array)
+    True
+    """
+    length = length or len(array)
+    swapped = False
+    for i in range(length - 1):
+        if array[i] > array[i + 1]:
+            array[i], array[i + 1] = (
+                array[i + 1],
+                array[i],
+            )
+            swapped = True
+    return array if not swapped else bubble_sort(array, length - 1)
+
+
+if __name__ == "__main__":
+    from doctest import testmod
+
+    testmod()