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d7a75da8ef
* Added doctests to bucket sort
* Missing typehint
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* Update bucket_sort.py
* updating DIRECTORY.md
* Update bucket_sort.py
Co-authored-by: Christian Clauss <cclauss@me.com>
Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
70 lines
2.3 KiB
Python
70 lines
2.3 KiB
Python
#!/usr/bin/env python3
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"""
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Illustrate how to implement bucket sort algorithm.
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Author: OMKAR PATHAK
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This program will illustrate how to implement bucket sort algorithm
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Wikipedia says: Bucket sort, or bin sort, is a sorting algorithm that works
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by distributing the elements of an array into a number of buckets.
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Each bucket is then sorted individually, either using a different sorting
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algorithm, or by recursively applying the bucket sorting algorithm. It is a
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distribution sort, and is a cousin of radix sort in the most to least
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significant digit flavour.
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Bucket sort is a generalization of pigeonhole sort. Bucket sort can be
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implemented with comparisons and therefore can also be considered a
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comparison sort algorithm. The computational complexity estimates involve the
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number of buckets.
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Time Complexity of Solution:
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Worst case scenario occurs when all the elements are placed in a single bucket.
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The overall performance would then be dominated by the algorithm used to sort each
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bucket. In this case, O(n log n), because of TimSort
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Average Case O(n + (n^2)/k + k), where k is the number of buckets
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If k = O(n), time complexity is O(n)
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Source: https://en.wikipedia.org/wiki/Bucket_sort
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"""
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DEFAULT_BUCKET_SIZE = 5
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def bucket_sort(my_list: list, bucket_size: int = DEFAULT_BUCKET_SIZE) -> list:
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"""
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>>> data = [-1, 2, -5, 0]
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>>> bucket_sort(data) == sorted(data)
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True
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>>> data = [9, 8, 7, 6, -12]
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>>> bucket_sort(data) == sorted(data)
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True
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>>> data = [.4, 1.2, .1, .2, -.9]
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>>> bucket_sort(data) == sorted(data)
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True
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>>> bucket_sort([])
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Traceback (most recent call last):
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...
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Exception: Please add some elements in the array.
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"""
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if len(my_list) == 0:
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raise Exception("Please add some elements in the array.")
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min_value, max_value = (min(my_list), max(my_list))
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bucket_count = (max_value - min_value) // bucket_size + 1
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buckets = [[] for _ in range(int(bucket_count))]
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for i in range(len(my_list)):
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buckets[int((my_list[i] - min_value) // bucket_size)].append(my_list[i])
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return sorted(
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buckets[i][j] for i in range(len(buckets)) for j in range(len(buckets[i]))
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)
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if __name__ == "__main__":
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assert bucket_sort([4, 5, 3, 2, 1]) == [1, 2, 3, 4, 5]
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assert bucket_sort([0, 1, -10, 15, 2, -2]) == [-10, -2, 0, 1, 2, 15]
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