From 7bfc8fd0bbc1e435f5fd579692bd2ac354b96b1e Mon Sep 17 00:00:00 2001
From: modusensus <guanqishi26@gmail.com>
Date: Sat, 19 Sep 2026 15:27:44 +0800
Subject: [PATCH] sorts: make merge_insertion_sort generic over Comparable
 items

---
 sorts/merge_insertion_sort.py | 14 ++++++++++----
 tests/test_sorts.py           |  3 +++
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/sorts/merge_insertion_sort.py b/sorts/merge_insertion_sort.py
index be71303a5a49..d17a341f2165 100644
--- a/sorts/merge_insertion_sort.py
+++ b/sorts/merge_insertion_sort.py
@@ -13,8 +13,14 @@
 
 from __future__ import annotations
 
+from typing import Any, Protocol
 
-def binary_search_insertion(sorted_list, item):
+
+class Comparable(Protocol):
+    def __lt__(self, other: Any, /) -> bool: ...
+
+
+def binary_search_insertion[T: Comparable](sorted_list: list[T], item: T) -> list[T]:
     """
     >>> binary_search_insertion([1, 2, 7, 9, 10], 4)
     [1, 2, 4, 7, 9, 10]
@@ -35,7 +41,7 @@ def binary_search_insertion(sorted_list, item):
     return sorted_list
 
 
-def merge(left, right):
+def merge[T: Comparable](left: list[list[T]], right: list[list[T]]) -> list[list[T]]:
     """
     >>> merge([[1, 6], [9, 10]], [[2, 3], [4, 5], [7, 8]])
     [[1, 6], [2, 3], [4, 5], [7, 8], [9, 10]]
@@ -49,7 +55,7 @@ def merge(left, right):
     return result + left + right
 
 
-def sortlist_2d(list_2d):
+def sortlist_2d[T: Comparable](list_2d: list[list[T]]) -> list[list[T]]:
     """
     >>> sortlist_2d([[9, 10], [1, 6], [7, 8], [2, 3], [4, 5]])
     [[1, 6], [2, 3], [4, 5], [7, 8], [9, 10]]
@@ -61,7 +67,7 @@ def sortlist_2d(list_2d):
     return merge(sortlist_2d(list_2d[:middle]), sortlist_2d(list_2d[middle:]))
 
 
-def merge_insertion_sort(collection: list[int]) -> list[int]:
+def merge_insertion_sort[T: Comparable](collection: list[T]) -> list[T]:
     """Pure implementation of merge-insertion sort algorithm in Python
 
     :param collection: some mutable ordered collection with heterogeneous
diff --git a/tests/test_sorts.py b/tests/test_sorts.py
index d18be1c22b83..8e55d9e90fc7 100644
--- a/tests/test_sorts.py
+++ b/tests/test_sorts.py
@@ -35,6 +35,7 @@
 from sorts.heap_sort import heap_sort
 from sorts.insertion_sort import insertion_sort
 from sorts.iterative_merge_sort import iter_merge_sort
+from sorts.merge_insertion_sort import merge_insertion_sort
 from sorts.merge_sort import merge_sort
 from sorts.odd_even_sort import odd_even_sort
 from sorts.odd_even_transposition_single_threaded import odd_even_transposition
@@ -73,6 +74,7 @@ def test_heap_sort() -> None:
     insertion_sort,
     iter_merge_sort,
     merge,
+    merge_insertion_sort,
     merge_sort,
     odd_even_sort,
     odd_even_transposition,
@@ -145,6 +147,7 @@ def test_rec_insertion_sort(case) -> None:
         gnome_sort,
         insertion_sort,
         merge,
+        merge_insertion_sort,
         merge_sort,
         odd_even_sort,
         odd_even_transposition,