mirror of
https://github.com/TheAlgorithms/Python.git
synced 2026-09-28 13:33:11 +08:00
Ashwin R
dbf22d3c48
* sorts: make heap sort support comparable items * style: remove unnecessary blank lines from heap sort
83 lines
2.3 KiB
Python
83 lines
2.3 KiB
Python
"""
|
|
A pure Python implementation of the heap sort algorithm.
|
|
"""
|
|
|
|
from typing import Protocol
|
|
|
|
|
|
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 comparable items
|
|
:param index: index
|
|
:param heap_size: size of the heap
|
|
:return: None
|
|
>>> unsorted = [1, 4, 3, 5, 2]
|
|
>>> heapify(unsorted, 0, len(unsorted))
|
|
>>> unsorted
|
|
[4, 5, 3, 1, 2]
|
|
>>> heapify(unsorted, 0, len(unsorted))
|
|
>>> unsorted
|
|
[5, 4, 3, 1, 2]
|
|
"""
|
|
largest = index
|
|
left_index = 2 * index + 1
|
|
right_index = 2 * index + 2
|
|
|
|
if left_index < heap_size and unsorted[largest] < unsorted[left_index]:
|
|
largest = left_index
|
|
|
|
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[T: Comparable](unsorted: list[T]) -> list[T]:
|
|
"""
|
|
A pure Python implementation of the heap sort algorithm.
|
|
|
|
:param unsorted: a mutable collection of comparable items
|
|
:return: the same collection ordered by ascending
|
|
|
|
Examples:
|
|
>>> heap_sort([0, 5, 3, 2, 2])
|
|
[0, 2, 2, 3, 5]
|
|
>>> heap_sort([])
|
|
[]
|
|
>>> heap_sort([-2, -5, -45])
|
|
[-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
|
|
|
|
|
|
if __name__ == "__main__":
|
|
import doctest
|
|
|
|
doctest.testmod()
|
|
user_input = input("Enter numbers separated by a comma:\n").strip()
|
|
if user_input:
|
|
unsorted = [int(item) for item in user_input.split(",")]
|
|
print(f"{heap_sort(unsorted) = }")
|