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* ci(pre-commit): Add ``flake8-builtins`` additional dependency to ``pre-commit`` (#7104) * refactor: Fix ``flake8-builtins`` (#7104) * fix(lru_cache): Fix naming conventions in docstrings (#7104) * ci(pre-commit): Order additional dependencies alphabetically (#7104) * fix(lfu_cache): Correct function name in docstring (#7104) * Update strings/snake_case_to_camel_pascal_case.py Co-authored-by: Christian Clauss <cclauss@me.com> * Update data_structures/stacks/next_greater_element.py Co-authored-by: Christian Clauss <cclauss@me.com> * Update digital_image_processing/index_calculation.py Co-authored-by: Christian Clauss <cclauss@me.com> * Update graphs/prim.py Co-authored-by: Christian Clauss <cclauss@me.com> * Update hashes/djb2.py Co-authored-by: Christian Clauss <cclauss@me.com> * refactor: Rename `_builtin` to `builtin_` ( #7104) * fix: Rename all instances (#7104) * refactor: Update variable names (#7104) * [pre-commit.ci] auto fixes from pre-commit.com hooks for more information, see https://pre-commit.ci * ci: Create ``tox.ini`` and ignore ``A003`` (#7123) * revert: Remove function name changes (#7104) * [pre-commit.ci] auto fixes from pre-commit.com hooks for more information, see https://pre-commit.ci * Rename tox.ini to .flake8 * Update data_structures/heap/heap.py Co-authored-by: Dhruv Manilawala <dhruvmanila@gmail.com> * refactor: Rename `next_` to `next_item` (#7104) * ci(pre-commit): Add `flake8` plugin `flake8-bugbear` (#7127) * refactor: Follow `flake8-bugbear` plugin (#7127) * fix: Correct `knapsack` code (#7127) * [pre-commit.ci] auto fixes from pre-commit.com hooks for more information, see https://pre-commit.ci Co-authored-by: Christian Clauss <cclauss@me.com> Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com> Co-authored-by: Dhruv Manilawala <dhruvmanila@gmail.com>
57 lines
1.6 KiB
Python
57 lines
1.6 KiB
Python
"""
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This is a pure Python implementation of the greedy-merge-sort algorithm
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reference: https://www.geeksforgeeks.org/optimal-file-merge-patterns/
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For doctests run following command:
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python3 -m doctest -v greedy_merge_sort.py
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Objective
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Merge a set of sorted files of different length into a single sorted file.
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We need to find an optimal solution, where the resultant file
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will be generated in minimum time.
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Approach
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If the number of sorted files are given, there are many ways
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to merge them into a single sorted file.
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This merge can be performed pair wise.
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To merge a m-record file and a n-record file requires possibly m+n record moves
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the optimal choice being,
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merge the two smallest files together at each step (greedy approach).
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"""
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def optimal_merge_pattern(files: list) -> float:
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"""Function to merge all the files with optimum cost
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Args:
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files [list]: A list of sizes of different files to be merged
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Returns:
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optimal_merge_cost [int]: Optimal cost to merge all those files
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Examples:
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>>> optimal_merge_pattern([2, 3, 4])
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14
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>>> optimal_merge_pattern([5, 10, 20, 30, 30])
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205
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>>> optimal_merge_pattern([8, 8, 8, 8, 8])
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96
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"""
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optimal_merge_cost = 0
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while len(files) > 1:
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temp = 0
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# Consider two files with minimum cost to be merged
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for _ in range(2):
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min_index = files.index(min(files))
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temp += files[min_index]
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files.pop(min_index)
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files.append(temp)
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optimal_merge_cost += temp
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return optimal_merge_cost
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if __name__ == "__main__":
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import doctest
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doctest.testmod()
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