Create stalin_sort.py (#11989)

* Create stalin_sort.py * [pre-commit.ci] auto fixes from pre-commit.com hooks for more information, see https://pre-commit.ci * Update stalin_sort.py * updating DIRECTORY.md * Update stalin_sort.py --------- Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com> Co-authored-by: Maxim Smolskiy <mithridatus@mail.ru> Co-authored-by: MaximSmolskiy <MaximSmolskiy@users.noreply.github.com>

Author: 3 people

DIRECTORY.md

@@ -1301,6 +1301,7 @@
  * [Shell Sort](sorts/shell_sort.py)
  * [Shrink Shell Sort](sorts/shrink_shell_sort.py)
  * [Slowsort](sorts/slowsort.py)
+ * [Stalin Sort](sorts/stalin_sort.py)
  * [Stooge Sort](sorts/stooge_sort.py)
  * [Strand Sort](sorts/strand_sort.py)
  * [Tim Sort](sorts/tim_sort.py)

sorts/stalin_sort.py

@@ -0,0 +1,47 @@
+"""
+Stalin Sort algorithm: Removes elements that are out of order.
+Elements that are not greater than or equal to the previous element are discarded.
+Reference: https://medium.com/@kaweendra/the-ultimate-sorting-algorithm-6513d6968420
+"""
+
+
+def stalin_sort(sequence: list[int]) -> list[int]:
+ """
+ Sorts a list using the Stalin sort algorithm.
+
+ >>> stalin_sort([4, 3, 5, 2, 1, 7])
+ [4, 5, 7]
+
+ >>> stalin_sort([1, 2, 3, 4])
+ [1, 2, 3, 4]
+
+ >>> stalin_sort([4, 5, 5, 2, 3])
+ [4, 5, 5]
+
+ >>> stalin_sort([6, 11, 12, 4, 1, 5])
+ [6, 11, 12]
+
+ >>> stalin_sort([5, 0, 4, 3])
+ [5]
+
+ >>> stalin_sort([5, 4, 3, 2, 1])
+ [5]
+
+ >>> stalin_sort([1, 2, 3, 4, 5])
+ [1, 2, 3, 4, 5]
+
+ >>> stalin_sort([1, 2, 8, 7, 6])
+ [1, 2, 8]
+ """
+ result = [sequence[0]]
+ for element in sequence[1:]:
+ if element >= result[-1]:
+ result.append(element)
+
+ return result
+
+
+if __name__ == "__main__":
+ import doctest
+
+ doctest.testmod()