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1f8a21d727
* Tighten up psf/black and flake8
* Fix some tests
* Fix some E741
* Fix some E741
* updating DIRECTORY.md
Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
47 lines
1.4 KiB
Python
47 lines
1.4 KiB
Python
def aliquot_sum(input_num: int) -> int:
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"""
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Finds the aliquot sum of an input integer, where the
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aliquot sum of a number n is defined as the sum of all
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natural numbers less than n that divide n evenly. For
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example, the aliquot sum of 15 is 1 + 3 + 5 = 9. This is
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a simple O(n) implementation.
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@param input_num: a positive integer whose aliquot sum is to be found
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@return: the aliquot sum of input_num, if input_num is positive.
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Otherwise, raise a ValueError
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Wikipedia Explanation: https://en.wikipedia.org/wiki/Aliquot_sum
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>>> aliquot_sum(15)
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9
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>>> aliquot_sum(6)
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6
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>>> aliquot_sum(-1)
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Traceback (most recent call last):
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...
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ValueError: Input must be positive
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>>> aliquot_sum(0)
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Traceback (most recent call last):
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...
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ValueError: Input must be positive
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>>> aliquot_sum(1.6)
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Traceback (most recent call last):
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...
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ValueError: Input must be an integer
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>>> aliquot_sum(12)
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16
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>>> aliquot_sum(1)
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0
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>>> aliquot_sum(19)
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1
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"""
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if not isinstance(input_num, int):
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raise ValueError("Input must be an integer")
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if input_num <= 0:
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raise ValueError("Input must be positive")
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return sum(divisor for divisor in range(1, input_num) if input_num % divisor == 0)
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if __name__ == "__main__":
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import doctest
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doctest.testmod()
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