sorts: make quick sort support comparable items

sorts/heap_sort.py

@@ -2,10 +2,16 @@
 A pure Python implementation of the heap sort algorithm.
 """
 
+from typing import Protocol
 
-def heapify(unsorted: list[int], index: int, heap_size: int) -> None:
+
+class Comparable(Protocol):
+    def __lt__(self, other: object, /) -> bool: ...
+
+
+def heapify[T: Comparable](unsorted: list[T], index: int, heap_size: int) -> None:
     """
-    :param unsorted: unsorted list containing integers numbers
+    :param unsorted: unsorted list containing comparable items
     :param index: index
     :param heap_size: size of the heap
     :return: None
@@ -20,22 +26,23 @@ def heapify(unsorted: list[int], index: int, heap_size: int) -> None:
     largest = index
     left_index = 2 * index + 1
     right_index = 2 * index + 2
-    if left_index < heap_size and unsorted[left_index] > unsorted[largest]:
+
+    if left_index < heap_size and unsorted[largest] < unsorted[left_index]:
         largest = left_index
 
-    if right_index < heap_size and unsorted[right_index] > unsorted[largest]:
+    if right_index < heap_size and unsorted[largest] < unsorted[right_index]:
         largest = right_index
 
     if largest != index:
         unsorted[largest], unsorted[index] = (unsorted[index], unsorted[largest])
         heapify(unsorted, largest, heap_size)
 
 
-def heap_sort(unsorted: list[int]) -> list[int]:
+def heap_sort[T: Comparable](unsorted: list[T]) -> list[T]:
     """
-    A pure Python implementation of the heap sort algorithm
+    A pure Python implementation of the heap sort algorithm.
 
-    :param collection: a mutable ordered collection of heterogeneous comparable items
+    :param unsorted: a mutable collection of comparable items
     :return: the same collection ordered by ascending
 
     Examples:
@@ -47,13 +54,24 @@ def heap_sort(unsorted: list[int]) -> list[int]:
     [-45, -5, -2]
     >>> heap_sort([3, 7, 9, 28, 123, -5, 8, -30, -200, 0, 4])
     [-200, -30, -5, 0, 3, 4, 7, 8, 9, 28, 123]
+    >>> heap_sort(["banana", "apple", "cherry"])
+    ['apple', 'banana', 'cherry']
+    >>> heap_sort([3.14, 1.5, 2.7])
+    [1.5, 2.7, 3.14]
+    >>> heap_sort([1, "two"])  # doctest: +ELLIPSIS
+    Traceback (most recent call last):
+    ...
+    TypeError: ...
     """
     n = len(unsorted)
+
     for i in range(n // 2 - 1, -1, -1):
         heapify(unsorted, i, n)
+
     for i in range(n - 1, 0, -1):
         unsorted[0], unsorted[i] = unsorted[i], unsorted[0]
         heapify(unsorted, 0, i)
+
     return unsorted
 
 

sorts/quick_sort.py

@@ -11,9 +11,14 @@
 from __future__ import annotations
 
 from random import randrange
+from typing import Protocol
 
 
-def quick_sort(collection: list) -> list:
+class Comparable(Protocol):
+    def __lt__(self, other: object, /) -> 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
@@ -26,18 +31,26 @@ def quick_sort(collection: list) -> list:
     []
     >>> quick_sort([-2, 5, 0, -45])
     [-45, -2, 0, 5]
+    >>> quick_sort(["banana", "apple", "cherry"])
+    ['apple', 'banana', 'cherry']
+    >>> quick_sort([3.14, 1.5, 2.7])
+    [1.5, 2.7, 3.14]
+    >>> quick_sort([1, "two"])  # doctest: +ELLIPSIS
+    Traceback (most recent call last):
+    ...
+    TypeError: '<' not supported between instances of ...
     """
     # 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
+    # Randomly select a pivot index and remove the pivot element
     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]
+    # Partition the remaining elements using the less-than comparison
+    lesser = [item for item in collection if item < pivot]
+    greater = [item for item in collection if not item < pivot]
 
     # Recursively sort the lesser and greater groups, and combine with the pivot
     return [*quick_sort(lesser), pivot, *quick_sort(greater)]