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* Code Enhancements in merge_sort.py This enhanced code includes improved variable naming, error handling for user input, and more detailed docstrings. It's now more robust and readable. * [pre-commit.ci] auto fixes from pre-commit.com hooks for more information, see https://pre-commit.ci --------- Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
64 lines
1.7 KiB
Python
64 lines
1.7 KiB
Python
"""
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This is a pure Python implementation of the merge sort algorithm.
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For doctests run following command:
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python -m doctest -v merge_sort.py
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or
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python3 -m doctest -v merge_sort.py
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For manual testing run:
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python merge_sort.py
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"""
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def merge_sort(collection: list) -> list:
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"""
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Sorts a list using the merge sort algorithm.
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:param collection: A mutable ordered collection with comparable items.
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:return: The same collection ordered in ascending order.
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Time Complexity: O(n log n)
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Examples:
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>>> merge_sort([0, 5, 3, 2, 2])
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[0, 2, 2, 3, 5]
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>>> merge_sort([])
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[]
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>>> merge_sort([-2, -5, -45])
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[-45, -5, -2]
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"""
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def merge(left: list, right: list) -> list:
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"""
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Merge two sorted lists into a single sorted list.
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:param left: Left collection
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:param right: Right collection
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:return: Merged result
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"""
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result = []
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while left and right:
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result.append(left.pop(0) if left[0] <= right[0] else right.pop(0))
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result.extend(left)
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result.extend(right)
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return result
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if len(collection) <= 1:
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return collection
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mid_index = len(collection) // 2
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return merge(merge_sort(collection[:mid_index]), merge_sort(collection[mid_index:]))
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if __name__ == "__main__":
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import doctest
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doctest.testmod()
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try:
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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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sorted_list = merge_sort(unsorted)
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print(*sorted_list, sep=",")
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except ValueError:
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print("Invalid input. Please enter valid integers separated by commas.")
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