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59 lines
1.5 KiB
Python
59 lines
1.5 KiB
Python
"""
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This is a pure python implementation of the shell sort algorithm
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For doctests run following command:
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python -m doctest -v shell_sort.py
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or
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python3 -m doctest -v shell_sort.py
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For manual testing run:
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python shell_sort.py
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"""
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from __future__ import print_function
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def shell_sort(collection):
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"""Pure implementation of shell 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 ordered by ascending
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>>> shell_sort([0, 5, 3, 2, 2)]
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[0, 2, 2, 3, 5]
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>>> shell_sort([])
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[]
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>>> shell_sort([-2, -5, -45])
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[-45, -5, -2]
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"""
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# Marcin Ciura's gap sequence
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gaps = [701, 301, 132, 57, 23, 10, 4, 1]
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for gap in gaps:
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i = gap
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while i < len(collection):
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temp = collection[i]
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j = i
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while j >= gap and collection[j-gap] > temp:
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collection[j] = collection[j - gap]
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j -= gap
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collection[j] = temp
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i += 1
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return collection
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if __name__ == '__main__':
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import sys
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# For python 2.x and 3.x compatibility: 3.x has not raw_input builtin
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# otherwise 2.x's input builtin function is too "smart"
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if sys.version_info.major < 3:
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input_function = raw_input
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else:
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input_function = input
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user_input = input_function('Enter numbers separated by a comma:\n')
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unsorted = [int(item) for item in user_input.split(',')]
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print(shell_sort(unsorted))
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