From e7015a7ca13e20e6313862555ce4be0d2ebf24ec Mon Sep 17 00:00:00 2001 From: K M PRADHYUT Date: Fri, 18 Sep 2026 06:17:33 +0530 Subject: [PATCH] sorts: make quick_sort work with any Comparable, not just int (#15327) * sorts: make quick_sort work with any Comparable, not just int Use a Comparable Protocol + TypeVar bound so that quick_sort correctly expresses it can sort any orderable type, not just integers. Simplifies partitioning to cleaner lesser/equal/greater lists and adds string + float doctest examples. Part of #15234 * fix: use PEP 695 type params, remove TypeVar import --- sorts/quick_sort.py | 32 ++++++++++++++++++-------------- 1 file changed, 18 insertions(+), 14 deletions(-) diff --git a/sorts/quick_sort.py b/sorts/quick_sort.py index 374d52e75..e5e225405 100644 --- a/sorts/quick_sort.py +++ b/sorts/quick_sort.py @@ -11,9 +11,14 @@ python3 quick_sort.py from __future__ import annotations from random import randrange +from typing import Any, Protocol -def quick_sort(collection: list) -> list: +class Comparable(Protocol): + def __lt__(self, other: Any, /) -> bool: ... + + +def quick_sort[T: Comparable](collection: list[T]) -> list[T]: """A pure Python implementation of quicksort algorithm. :param collection: a mutable collection of comparable items @@ -26,27 +31,26 @@ def quick_sort(collection: list) -> list: [] >>> quick_sort([-2, 5, 0, -45]) [-45, -2, 0, 5] + >>> quick_sort(["z", "a", "m", "b"]) + ['a', 'b', 'm', 'z'] + >>> quick_sort([3.14, -1.0, 2.71]) + [-1.0, 2.71, 3.14] + >>> quick_sort([0, 5, 3, 2, 2]) == sorted([0, 5, 3, 2, 2]) + True + >>> quick_sort(["z", "a", "m"]) == sorted(["z", "a", "m"]) + True """ - # Base case: if the collection has 0 or 1 elements, it is already sorted if len(collection) < 2: return collection - - # Randomly select a pivot index and remove the pivot element from the collection pivot_index = randrange(len(collection)) - pivot = collection.pop(pivot_index) - - # Partition the remaining elements into two groups: lesser or equal, and greater - lesser = [item for item in collection if item <= pivot] + pivot = collection[pivot_index] + lesser = [item for item in collection if item < pivot] + equal = [item for item in collection if item == pivot] greater = [item for item in collection if item > pivot] - - # Recursively sort the lesser and greater groups, and combine with the pivot - return [*quick_sort(lesser), pivot, *quick_sort(greater)] + return [*quick_sort(lesser), *equal, *quick_sort(greater)] if __name__ == "__main__": - # Get user input and convert it into a list of integers user_input = input("Enter numbers separated by a comma:\n").strip() unsorted = [int(item) for item in user_input.split(",")] - - # Print the result of sorting the user-provided list print(quick_sort(unsorted))