mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-10-06 05:39:30 +00:00
b3dc6ef035
* fixes #9002; improve insertion_sort algorithm * add type hints to sorts/insertion_sort.py
71 lines
2.1 KiB
Python
71 lines
2.1 KiB
Python
"""
|
|
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
|
|
|
|
|
|
class Comparable(Protocol):
|
|
def __lt__(self, other: Any, /) -> bool:
|
|
...
|
|
|
|
|
|
T = TypeVar("T", bound=Comparable)
|
|
|
|
|
|
def insertion_sort(collection: MutableSequence[T]) -> MutableSequence[T]:
|
|
"""A pure Python implementation of the insertion sort algorithm
|
|
|
|
:param collection: some mutable ordered collection with heterogeneous
|
|
comparable items inside
|
|
:return: the same collection ordered by ascending
|
|
|
|
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
|
|
"""
|
|
|
|
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
|
|
|
|
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) = }")
|