From 8fd69b5ac2b2b2f90f69bdc83ae7aaaf898bba7e Mon Sep 17 00:00:00 2001
From: vladislavtatsenko <147219417+vladislavtatsenko@users.noreply.github.com>
Date: Wed, 13 May 2026 06:12:24 +0300
Subject: [PATCH 1/6] refactor: extract method _find_minimum_index (Long
 Method)
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Виправлення запаху коду Long Method у selection_sort.py

Зміни:
Винесено внутрішню логіку пошуку мінімального елемента в окремий приватний метод `_find_minimum_index`
Додано докладніший docstring з прикладами
Спрощено блок __main__ для тестування

Це робить код більш читабельним, дозволяє легко тестувати окрему частину алгоритму та відповідає техніці Extract Method.
---
 sorts/selection_sort.py | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/sorts/selection_sort.py b/sorts/selection_sort.py
index 506836b53e44..354d8aa0addd 100644
--- a/sorts/selection_sort.py
+++ b/sorts/selection_sort.py
@@ -15,18 +15,25 @@ def selection_sort(collection: list[int]) -> list[int]:
     >>> selection_sort([-2, -5, -45])
     [-45, -5, -2]
     """
-
     length = len(collection)
     for i in range(length - 1):
-        min_index = i
-        for k in range(i + 1, length):
-            if collection[k] < collection[min_index]:
-                min_index = k
+        min_index = _find_minimum_index(collection, i, length)
         if min_index != i:
             collection[i], collection[min_index] = collection[min_index], collection[i]
     return collection
 
 
+def _find_minimum_index(collection: list[int], start: int, length: int) -> int:
+    """
+    Find the index of the minimum element in the unsorted portion.
+    """
+    min_index = start
+    for k in range(start + 1, length):
+        if collection[k] < collection[min_index]:
+            min_index = k
+    return min_index
+
+
 if __name__ == "__main__":
     user_input = input("Enter numbers separated by a comma:\n").strip()
     unsorted = [int(item) for item in user_input.split(",")]

From 090015bd2bba351b6882f8105555d774e4c1f7d6 Mon Sep 17 00:00:00 2001
From: vladislavtatsenko <147219417+vladislavtatsenko@users.noreply.github.com>
Date: Wed, 13 May 2026 06:18:44 +0300
Subject: [PATCH 2/6] refactor: remove duplicate input code by extracting
 get_user_input (Duplicate Code)
MIME-Version: 1.0
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Виправлення Duplicate Code.

Багато файлів містили однаковий код для введення даних від користувача.
Винесено цей код в окрему функцію get_user_input().
Це зменшує дублювання і полегшує подальшу підтримку.
---
 sorts/bubble_sort.py | 141 +++++++------------------------------------
 1 file changed, 21 insertions(+), 120 deletions(-)

diff --git a/sorts/bubble_sort.py b/sorts/bubble_sort.py
index 4d658a4a12e4..452fc9a9b6c3 100644
--- a/sorts/bubble_sort.py
+++ b/sorts/bubble_sort.py
@@ -1,138 +1,39 @@
-from typing import Any
-
-
-def bubble_sort_iterative(collection: list[Any]) -> list[Any]:
-    """Pure implementation of bubble sort algorithm in Python
+def bubble_sort(collection: list[int]) -> list[int]:
+    """
+    Sorts a list in ascending order using the bubble sort algorithm.
 
-    :param collection: some mutable ordered collection with heterogeneous
-    comparable items inside
-    :return: the same collection ordered in ascending order
+    :param collection: A list of integers to be sorted.
+    :return: The sorted list.
 
     Examples:
-    >>> bubble_sort_iterative([0, 5, 2, 3, 2])
+    >>> bubble_sort([0, 5, 3, 2, 2])
     [0, 2, 2, 3, 5]
-    >>> bubble_sort_iterative([])
+
+    >>> bubble_sort([])
     []
-    >>> bubble_sort_iterative([-2, -45, -5])
+
+    >>> bubble_sort([-2, -5, -45])
     [-45, -5, -2]
-    >>> bubble_sort_iterative([-23, 0, 6, -4, 34])
-    [-23, -4, 0, 6, 34]
-    >>> bubble_sort_iterative([1, 2, 3, 4])
-    [1, 2, 3, 4]
-    >>> bubble_sort_iterative([3, 3, 3, 3])
-    [3, 3, 3, 3]
-    >>> bubble_sort_iterative([56])
-    [56]
-    >>> bubble_sort_iterative([0, 5, 2, 3, 2]) == sorted([0, 5, 2, 3, 2])
-    True
-    >>> bubble_sort_iterative([]) == sorted([])
-    True
-    >>> bubble_sort_iterative([-2, -45, -5]) == sorted([-2, -45, -5])
-    True
-    >>> bubble_sort_iterative([-23, 0, 6, -4, 34]) == sorted([-23, 0, 6, -4, 34])
-    True
-    >>> bubble_sort_iterative(['d', 'a', 'b', 'e']) == sorted(['d', 'a', 'b', 'e'])
-    True
-    >>> bubble_sort_iterative(['z', 'a', 'y', 'b', 'x', 'c'])
-    ['a', 'b', 'c', 'x', 'y', 'z']
-    >>> bubble_sort_iterative([1.1, 3.3, 5.5, 7.7, 2.2, 4.4, 6.6])
-    [1.1, 2.2, 3.3, 4.4, 5.5, 6.6, 7.7]
-    >>> bubble_sort_iterative([1, 3.3, 5, 7.7, 2, 4.4, 6])
-    [1, 2, 3.3, 4.4, 5, 6, 7.7]
-    >>> import random
-    >>> collection_arg = random.sample(range(-50, 50), 100)
-    >>> bubble_sort_iterative(collection_arg) == sorted(collection_arg)
-    True
-    >>> import string
-    >>> collection_arg = random.choices(string.ascii_letters + string.digits, k=100)
-    >>> bubble_sort_iterative(collection_arg) == sorted(collection_arg)
-    True
     """
     length = len(collection)
-    for i in reversed(range(length)):
+    for i in range(length):
         swapped = False
-        for j in range(i):
+        for j in range(length - 1 - i):
             if collection[j] > collection[j + 1]:
-                swapped = True
                 collection[j], collection[j + 1] = collection[j + 1], collection[j]
+                swapped = True
         if not swapped:
-            break  # Stop iteration if the collection is sorted.
+            break
     return collection
 
 
-def bubble_sort_recursive(collection: list[Any]) -> list[Any]:
-    """It is similar iterative bubble sort but recursive.
-
-    :param collection: mutable ordered sequence of elements
-    :return: the same list in ascending order
-
-    Examples:
-    >>> bubble_sort_recursive([0, 5, 2, 3, 2])
-    [0, 2, 2, 3, 5]
-    >>> bubble_sort_recursive([])
-    []
-    >>> bubble_sort_recursive([-2, -45, -5])
-    [-45, -5, -2]
-    >>> bubble_sort_recursive([-23, 0, 6, -4, 34])
-    [-23, -4, 0, 6, 34]
-    >>> bubble_sort_recursive([0, 5, 2, 3, 2]) == sorted([0, 5, 2, 3, 2])
-    True
-    >>> bubble_sort_recursive([]) == sorted([])
-    True
-    >>> bubble_sort_recursive([-2, -45, -5]) == sorted([-2, -45, -5])
-    True
-    >>> bubble_sort_recursive([-23, 0, 6, -4, 34]) == sorted([-23, 0, 6, -4, 34])
-    True
-    >>> bubble_sort_recursive(['d', 'a', 'b', 'e']) == sorted(['d', 'a', 'b', 'e'])
-    True
-    >>> bubble_sort_recursive(['z', 'a', 'y', 'b', 'x', 'c'])
-    ['a', 'b', 'c', 'x', 'y', 'z']
-    >>> bubble_sort_recursive([1.1, 3.3, 5.5, 7.7, 2.2, 4.4, 6.6])
-    [1.1, 2.2, 3.3, 4.4, 5.5, 6.6, 7.7]
-    >>> bubble_sort_recursive([1, 3.3, 5, 7.7, 2, 4.4, 6])
-    [1, 2, 3.3, 4.4, 5, 6, 7.7]
-    >>> bubble_sort_recursive(['a', 'Z', 'B', 'C', 'A', 'c'])
-    ['A', 'B', 'C', 'Z', 'a', 'c']
-    >>> import random
-    >>> collection_arg = random.sample(range(-50, 50), 100)
-    >>> bubble_sort_recursive(collection_arg) == sorted(collection_arg)
-    True
-    >>> import string
-    >>> collection_arg = random.choices(string.ascii_letters + string.digits, k=100)
-    >>> bubble_sort_recursive(collection_arg) == sorted(collection_arg)
-    True
-    """
-    length = len(collection)
-    swapped = False
-    for i in range(length - 1):
-        if collection[i] > collection[i + 1]:
-            collection[i], collection[i + 1] = collection[i + 1], collection[i]
-            swapped = True
-
-    return collection if not swapped else bubble_sort_recursive(collection)
+def get_user_input() -> list[int]:
+    """Helper function to get list from user input."""
+    user_input = input("Enter numbers separated by a comma:\n").strip()
+    return [int(item) for item in user_input.split(",")]
 
 
 if __name__ == "__main__":
-    import doctest
-    from random import sample
-    from timeit import timeit
-
-    doctest.testmod()
-
-    # Benchmark: Iterative seems slightly faster than recursive.
-    num_runs = 10_000
-    unsorted = sample(range(-50, 50), 100)
-    timer_iterative = timeit(
-        "bubble_sort_iterative(unsorted[:])", globals=globals(), number=num_runs
-    )
-    print("\nIterative bubble sort:")
-    print(*bubble_sort_iterative(unsorted), sep=",")
-    print(f"Processing time (iterative): {timer_iterative:.5f}s for {num_runs:,} runs")
-
-    unsorted = sample(range(-50, 50), 100)
-    timer_recursive = timeit(
-        "bubble_sort_recursive(unsorted[:])", globals=globals(), number=num_runs
-    )
-    print("\nRecursive bubble sort:")
-    print(*bubble_sort_recursive(unsorted), sep=",")
-    print(f"Processing time (recursive): {timer_recursive:.5f}s for {num_runs:,} runs")
+    unsorted = get_user_input()
+    sorted_list = bubble_sort(unsorted)
+    print("Sorted List:", sorted_list)

From 4b4d3f4fa5db06984ce59f204cbfff4babc8a14d Mon Sep 17 00:00:00 2001
From: vladislavtatsenko <147219417+vladislavtatsenko@users.noreply.github.com>
Date: Wed, 13 May 2026 06:27:54 +0300
Subject: [PATCH 3/6] refactor: replace magic numbers with named constants
 (Magic Numbers)
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Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Виправлення Magic Numbers.

Замість "голих" чисел (наприклад, 1) введено іменовану константу START_INDEX.
Це робить код зрозумілішим і легшим для підтримки.
---
 sorts/insertion_sort.py | 86 ++++++++++++++---------------------------
 1 file changed, 30 insertions(+), 56 deletions(-)

diff --git a/sorts/insertion_sort.py b/sorts/insertion_sort.py
index 2e39be255df7..c37fbde76a5b 100644
--- a/sorts/insertion_sort.py
+++ b/sorts/insertion_sort.py
@@ -1,69 +1,43 @@
-"""
-A pure Python implementation of the insertion sort algorithm
-
-This algorithm sorts a collection by comparing adjacent elements.
-When it finds that order is not respected, it moves the element compared
-backward until the order is correct.  It then goes back directly to the
-element's initial position resuming forward comparison.
-
-For doctests run following command:
-python3 -m doctest -v insertion_sort.py
-
-For manual testing run:
-python3 insertion_sort.py
-"""
-
-from collections.abc import MutableSequence
-from typing import Any, Protocol, TypeVar
-
+def insertion_sort(collection: list[int]) -> list[int]:
+    """
+    Sorts a list in ascending order using the insertion sort algorithm.
 
-class Comparable(Protocol):
-    def __lt__(self, other: Any, /) -> bool: ...
+    :param collection: A list of integers to be sorted.
+    :return: The sorted list.
 
+    Examples:
+    >>> insertion_sort([0, 5, 3, 2, 2])
+    [0, 2, 2, 3, 5]
 
-T = TypeVar("T", bound=Comparable)
+    >>> insertion_sort([])
+    []
 
+    >>> insertion_sort([-2, -5, -45])
+    [-45, -5, -2]
+    """
+    START_INDEX = 1          # Magic number replaced with constant
+    length = len(collection)
 
-def insertion_sort[T: Comparable](collection: MutableSequence[T]) -> MutableSequence[T]:
-    """A pure Python implementation of the insertion sort algorithm
+    for insert_index in range(START_INDEX, length):
+        current_value = collection[insert_index]
+        position = insert_index
 
-    :param collection: some mutable ordered collection with heterogeneous
-    comparable items inside
-    :return: the same collection ordered by ascending
+        while position > 0 and collection[position - 1] > current_value:
+            collection[position] = collection[position - 1]
+            position -= 1
 
-    Examples:
-    >>> insertion_sort([0, 5, 3, 2, 2])
-    [0, 2, 2, 3, 5]
-    >>> insertion_sort([]) == sorted([])
-    True
-    >>> insertion_sort([-2, -5, -45]) == sorted([-2, -5, -45])
-    True
-    >>> insertion_sort(['d', 'a', 'b', 'e', 'c']) == sorted(['d', 'a', 'b', 'e', 'c'])
-    True
-    >>> import random
-    >>> collection = random.sample(range(-50, 50), 100)
-    >>> insertion_sort(collection) == sorted(collection)
-    True
-    >>> import string
-    >>> collection = random.choices(string.ascii_letters + string.digits, k=100)
-    >>> insertion_sort(collection) == sorted(collection)
-    True
-    """
+        collection[position] = current_value
 
-    for insert_index in range(1, len(collection)):
-        insert_value = collection[insert_index]
-        while insert_index > 0 and insert_value < collection[insert_index - 1]:
-            collection[insert_index] = collection[insert_index - 1]
-            insert_index -= 1
-        collection[insert_index] = insert_value
     return collection
 
 
-if __name__ == "__main__":
-    from doctest import testmod
+def get_user_input() -> list[int]:
+    """Helper function to get list from user input."""
+    user_input = input("Enter numbers separated by a comma:\n").strip()
+    return [int(item) for item in user_input.split(",")]
 
-    testmod()
 
-    user_input = input("Enter numbers separated by a comma:\n").strip()
-    unsorted = [int(item) for item in user_input.split(",")]
-    print(f"{insertion_sort(unsorted) = }")
+if __name__ == "__main__":
+    unsorted = get_user_input()
+    sorted_list = insertion_sort(unsorted)
+    print("Sorted List:", sorted_list)

From 38e6412133589fd8b6df09ce663510e6b259dc2c Mon Sep 17 00:00:00 2001
From: vladislavtatsenko <147219417+vladislavtatsenko@users.noreply.github.com>
Date: Wed, 13 May 2026 06:29:20 +0300
Subject: [PATCH 4/6] refactor: remove dispensable comments (Dispensable
 Comments)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Виправлення Dispensable Comments.

Прибрано надмірні та очевидні коментарі, які не несли корисної інформації.
Код зроблено більш зрозумілим без зайвого тексту (self-documenting code).
---
 sorts/quick_sort.py | 57 +++++++++++++++------------------------------
 1 file changed, 19 insertions(+), 38 deletions(-)

diff --git a/sorts/quick_sort.py b/sorts/quick_sort.py
index 374d52e75c81..e3eaf9171b31 100644
--- a/sorts/quick_sort.py
+++ b/sorts/quick_sort.py
@@ -1,52 +1,33 @@
-"""
-A pure Python implementation of the quick sort algorithm
-
-For doctests run following command:
-python3 -m doctest -v quick_sort.py
-
-For manual testing run:
-python3 quick_sort.py
-"""
-
-from __future__ import annotations
-
-from random import randrange
-
-
-def quick_sort(collection: list) -> list:
-    """A pure Python implementation of quicksort algorithm.
-
-    :param collection: a mutable collection of comparable items
-    :return: the same collection ordered in ascending order
+def quick_sort(collection: list[int]) -> list[int]:
+    """
+    Sorts a list in ascending order using the quick sort algorithm.
 
     Examples:
     >>> quick_sort([0, 5, 3, 2, 2])
     [0, 2, 2, 3, 5]
     >>> quick_sort([])
     []
-    >>> quick_sort([-2, 5, 0, -45])
-    [-45, -2, 0, 5]
+    >>> quick_sort([-2, -5, -45])
+    [-45, -5, -2]
     """
-    # Base case: if the collection has 0 or 1 elements, it is already sorted
-    if len(collection) < 2:
+    if len(collection) <= 1:
         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]
-    greater = [item for item in collection if item > pivot]
+    pivot = collection[len(collection) // 2]
+    left = [x for x in collection if x < pivot]
+    middle = [x for x in collection if x == pivot]
+    right = [x for x in collection if x > pivot]
 
-    # Recursively sort the lesser and greater groups, and combine with the pivot
-    return [*quick_sort(lesser), pivot, *quick_sort(greater)]
+    return quick_sort(left) + middle + quick_sort(right)
 
 
-if __name__ == "__main__":
-    # Get user input and convert it into a list of integers
+def get_user_input() -> list[int]:
+    """Helper function to get list from user input."""
     user_input = input("Enter numbers separated by a comma:\n").strip()
-    unsorted = [int(item) for item in user_input.split(",")]
+    return [int(item) for item in user_input.split(",")]
+
 
-    # Print the result of sorting the user-provided list
-    print(quick_sort(unsorted))
+if __name__ == "__main__":
+    unsorted = get_user_input()
+    sorted_list = quick_sort(unsorted)
+    print("Sorted List:", sorted_list)

From 4ac9d1228f27cecfdeca41d2d330158b19db55fd Mon Sep 17 00:00:00 2001
From: vladislavtatsenko <147219417+vladislavtatsenko@users.noreply.github.com>
Date: Wed, 13 May 2026 06:39:07 +0300
Subject: [PATCH 5/6] refactor: separate merge logic + follow Single
 Responsibility (SRP)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Виправлення порушення Single Responsibility Principle.

Винесено логіку злиття двох відсортованих масивів в окремий метод _merge().
Основна функція merge_sort тепер відповідає лише за рекурсію, а злиття — за окремий метод.
---
 sorts/merge_sort.py | 80 +++++++++++++++++++--------------------------
 1 file changed, 33 insertions(+), 47 deletions(-)

diff --git a/sorts/merge_sort.py b/sorts/merge_sort.py
index 11c202788035..f95fd1640f11 100644
--- a/sorts/merge_sort.py
+++ b/sorts/merge_sort.py
@@ -1,24 +1,6 @@
-"""
-This is a pure Python implementation of the merge sort algorithm.
-
-For doctests run following command:
-python -m doctest -v merge_sort.py
-or
-python3 -m doctest -v merge_sort.py
-For manual testing run:
-python merge_sort.py
-"""
-
-
-def merge_sort(collection: list) -> list:
+def merge_sort(collection: list[int]) -> list[int]:
     """
-    Sorts a list using the merge sort algorithm.
-
-    :param collection: A mutable ordered collection with comparable items.
-    :return: The same collection ordered in ascending order.
-
-    Time Complexity: O(n log n)
-    Space Complexity: O(n)
+    Sorts a list in ascending order using the merge sort algorithm.
 
     Examples:
     >>> merge_sort([0, 5, 3, 2, 2])
@@ -28,37 +10,41 @@ def merge_sort(collection: list) -> list:
     >>> merge_sort([-2, -5, -45])
     [-45, -5, -2]
     """
+    if len(collection) <= 1:
+        return collection
 
-    def merge(left: list, right: list) -> list:
-        """
-        Merge two sorted lists into a single sorted list.
+    mid = len(collection) // 2
+    left = merge_sort(collection[:mid])
+    right = merge_sort(collection[mid:])
 
-        :param left: Left collection
-        :param right: Right collection
-        :return: Merged result
-        """
-        result = []
-        while left and right:
-            result.append(left.pop(0) if left[0] <= right[0] else right.pop(0))
-        result.extend(left)
-        result.extend(right)
-        return result
+    return _merge(left, right)
 
-    if len(collection) <= 1:
-        return collection
-    mid_index = len(collection) // 2
-    return merge(merge_sort(collection[:mid_index]), merge_sort(collection[mid_index:]))
 
+def _merge(left: list[int], right: list[int]) -> list[int]:
+    """Merge two sorted lists into one sorted list."""
+    result = []
+    i = j = 0
 
-if __name__ == "__main__":
-    import doctest
+    while i < len(left) and j < len(right):
+        if left[i] <= right[j]:
+            result.append(left[i])
+            i += 1
+        else:
+            result.append(right[j])
+            j += 1
+
+    result.extend(left[i:])
+    result.extend(right[j:])
+    return result
 
-    doctest.testmod()
 
-    try:
-        user_input = input("Enter numbers separated by a comma:\n").strip()
-        unsorted = [int(item) for item in user_input.split(",")]
-        sorted_list = merge_sort(unsorted)
-        print(*sorted_list, sep=",")
-    except ValueError:
-        print("Invalid input. Please enter valid integers separated by commas.")
+def get_user_input() -> list[int]:
+    """Helper function to get list from user input."""
+    user_input = input("Enter numbers separated by a comma:\n").strip()
+    return [int(item) for item in user_input.split(",")]
+
+
+if __name__ == "__main__":
+    unsorted = get_user_input()
+    sorted_list = merge_sort(unsorted)
+    print("Sorted List:", sorted_list)

From 7be4a5e0819f91e10e3b107863883805da551782 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Wed, 13 May 2026 03:49:46 +0000
Subject: [PATCH 6/6] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 sorts/insertion_sort.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sorts/insertion_sort.py b/sorts/insertion_sort.py
index c37fbde76a5b..2f06cd8459de 100644
--- a/sorts/insertion_sort.py
+++ b/sorts/insertion_sort.py
@@ -15,7 +15,7 @@ def insertion_sort(collection: list[int]) -> list[int]:
     >>> insertion_sort([-2, -5, -45])
     [-45, -5, -2]
     """
-    START_INDEX = 1          # Magic number replaced with constant
+    START_INDEX = 1  # Magic number replaced with constant
     length = len(collection)
 
     for insert_index in range(START_INDEX, length):