sorts: type bitonic_sort's three functions for any comparable item

Part of #15234.

Author: Fayupable

sorts/bitonic_sort.py

@@ -6,8 +6,16 @@
 
 from __future__ import annotations
 
+from typing import Protocol
 
-def comp_and_swap(array: list[int], index1: int, index2: int, direction: int) -> None:
+
+class Comparable(Protocol):
+    def __lt__(self, other: object, /) -> bool: ...
+
+
+def comp_and_swap[T: Comparable](
+    array: list[T], index1: int, index2: int, direction: int
+) -> None:
     """Compare the value at given index1 and index2 of the array and swap them as per
     the given direction.
 
@@ -31,14 +39,26 @@ def comp_and_swap(array: list[int], index1: int, index2: int, direction: int) ->
     >>> comp_and_swap(arr, 0, 3, 0)
     >>> arr
     [12, 42, -21, 1]
+
+    >>> arr = ["d", "a", "c", "b"]
+    >>> comp_and_swap(arr, 0, 1, 1)
+    >>> arr
+    ['a', 'd', 'c', 'b']
+
+    >>> comp_and_swap([1, "a"], 0, 1, 1)  # doctest: +IGNORE_EXCEPTION_DETAIL
+    Traceback (most recent call last):
+        ...
+    TypeError: '<' not supported between instances of 'str' and 'int'
     """
     if (direction == 1 and array[index1] > array[index2]) or (
         direction == 0 and array[index1] < array[index2]
     ):
         array[index1], array[index2] = array[index2], array[index1]
 
 
-def bitonic_merge(array: list[int], low: int, length: int, direction: int) -> None:
+def bitonic_merge[T: Comparable](
+    array: list[T], low: int, length: int, direction: int
+) -> None:
     """
     It recursively sorts a bitonic sequence in ascending order, if direction = 1, and in
     descending if direction = 0.
@@ -62,7 +82,9 @@ def bitonic_merge(array: list[int], low: int, length: int, direction: int) -> No
         bitonic_merge(array, low + middle, middle, direction)
 
 
-def bitonic_sort(array: list[int], low: int, length: int, direction: int) -> None:
+def bitonic_sort[T: Comparable](
+    array: list[T], low: int, length: int, direction: int
+) -> None:
     """
     This function first produces a bitonic sequence by recursively sorting its two
     halves in opposite sorting orders, and then calls bitonic_merge to make them in the
@@ -76,6 +98,11 @@ def bitonic_sort(array: list[int], low: int, length: int, direction: int) -> Non
     >>> bitonic_sort(arr, 0, 8, 0)
     >>> arr
     [145, 92, 34, 12, 0, -23, -121, -167]
+
+    >>> arr = [3.3, 1.1, 4.4, 2.2]
+    >>> bitonic_sort(arr, 0, 4, 1)
+    >>> arr
+    [1.1, 2.2, 3.3, 4.4]
     """
     if length > 1:
         middle = int(length / 2)