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