sorts: make strand sort work with comparable types (#15350)

* sorts: make strand sort work with comparable types

* Add type parameter to strand_sort function

* Add strand_sort to sorting tests

---------

Co-authored-by: nikhil.mewar@valiancesolutions.com <nikhil.mewar@valiancesolutions.com>
Co-authored-by: Christian Clauss <cclauss@me.com>

Author: 3 people

sorts/strand_sort.py

@@ -1,7 +1,19 @@
 import operator
+from typing import Protocol, TypeVar
 
 
-def strand_sort(arr: list, reverse: bool = False, solution: list | None = None) -> list:
+class Comparable(Protocol):
+    def __lt__(self, other: object, /) -> bool: ...
+
+    def __gt__(self, other: object, /) -> bool: ...
+
+
+T = TypeVar("T", bound=Comparable)
+
+
+def strand_sort[T](
+    arr: list[T], reverse: bool = False, solution: list[T] | None = None
+) -> list[T]:
     """
     Strand sort implementation
     source: https://en.wikipedia.org/wiki/Strand_sort
@@ -16,6 +28,10 @@ def strand_sort(arr: list, reverse: bool = False, solution: list | None = None)
 
     >>> strand_sort([4, 2, 5, 3, 0, 1], reverse=True)
     [5, 4, 3, 2, 1, 0]
+
+    >>> strand_sort(["banana", "apple", "cherry"])
+    ['apple', 'banana', 'cherry']
+
     """
     _operator = operator.lt if reverse else operator.gt
     solution = solution or []

tests/test_sorts.py

@@ -142,6 +142,7 @@ def test_rec_insertion_sort(case) -> None:
         pancake_sort,
         selection_sort,
         shrink_shell_sort,
+        strand_sort,
     ],
     ids=lambda f: f.__name__,
 )