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45 lines
1.5 KiB
Python
45 lines
1.5 KiB
Python
"""
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A Python implementation of the Reverse Selection Sort algorithm.
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This algorithm progressively sorts the array by finding the largest
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element and reversing subarrays to place it at the correct position.
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Inspired by the Pancake Sorting algorithm.
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For more information, see: https://en.wikipedia.org/wiki/Pancake_sorting
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Examples:
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>>> reverse_selection_sort([45, 23, 11, 89, 54, 1, 3, 36])
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[89, 54, 45, 36, 23, 11, 3, 1]
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>>> reverse_selection_sort([0, -89, 32, 5, 46, 8, 11])
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[46, 32, 11, 8, 5, 0, -89]
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>>> reverse_selection_sort([34, -2, -1, 98, -42])
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[98, 34, -1, -2, -42]
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"""
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def reverse_selection_sort(collection: list) -> list:
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"""
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A pure implementation of reverse selection sort algorithm in Python.
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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 sorted in descending order
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"""
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n = len(collection)
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for i in range(n):
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# Find the maximum element in the unsorted portion
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max_idx = i
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for j in range(i + 1, n):
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if collection[j] > collection[max_idx]:
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max_idx = j
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# Reverse the subarray from the current position to the end
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collection[i : max_idx + 1] = reversed(collection[i : max_idx + 1])
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return collection
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if __name__ == "__main__":
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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(reverse_selection_sort(unsorted))
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