Fix bucket sort (TheAlgorithms#2494)

* fixed bucket sort

* delete blank line

Author: realDuYuanChao

Diff for: sorts/bucket_sort.py

@@ -27,43 +27,41 @@
 
 Source: https://en.wikipedia.org/wiki/Bucket_sort
 """
-DEFAULT_BUCKET_SIZE = 5
 
 
-def bucket_sort(my_list: list, bucket_size: int = DEFAULT_BUCKET_SIZE) -> list:
+def bucket_sort(my_list: list) -> list:
     """
     >>> data = [-1, 2, -5, 0]
     >>> bucket_sort(data) == sorted(data)
     True
-
     >>> data = [9, 8, 7, 6, -12]
     >>> bucket_sort(data) == sorted(data)
     True
-
     >>> data = [.4, 1.2, .1, .2, -.9]
     >>> bucket_sort(data) == sorted(data)
     True
-
-    >>> bucket_sort([])
-    Traceback (most recent call last):
-      ...
-    Exception: Please add some elements in the array.
+    >>> bucket_sort([]) == sorted([])
+    True
+    >>> import random
+    >>> collection = random.sample(range(-50, 50), 50)
+    >>> bucket_sort(collection) == sorted(collection)
+    True
     """
     if len(my_list) == 0:
-        raise Exception("Please add some elements in the array.")
-
-    min_value, max_value = (min(my_list), max(my_list))
-    bucket_count = (max_value - min_value) // bucket_size + 1
-    buckets = [[] for _ in range(int(bucket_count))]
+        return []
+    min_value, max_value = min(my_list), max(my_list)
+    bucket_count = int(max_value - min_value) + 1
+    buckets = [[] for _ in range(bucket_count)]
 
     for i in range(len(my_list)):
-        buckets[int((my_list[i] - min_value) // bucket_size)].append(my_list[i])
+        buckets[(int(my_list[i] - min_value) // bucket_count)].append(my_list[i])
 
-    return sorted(
-        buckets[i][j] for i in range(len(buckets)) for j in range(len(buckets[i]))
-    )
+    return [v for bucket in buckets for v in sorted(bucket)]
 
 
 if __name__ == "__main__":
+    from doctest import testmod
+
+    testmod()
     assert bucket_sort([4, 5, 3, 2, 1]) == [1, 2, 3, 4, 5]
     assert bucket_sort([0, 1, -10, 15, 2, -2]) == [-10, -2, 0, 1, 2, 15]