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088b4201a1
* add alternate harmonic series * Add Alternating Harmonic Series * [pre-commit.ci] auto fixes from pre-commit.com hooks for more information, see https://pre-commit.ci --------- Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
58 lines
2.0 KiB
Python
58 lines
2.0 KiB
Python
def is_alternate_harmonic_series(series: list) -> bool:
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"""
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Web Biblography
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https://en.wikipedia.org/wiki/Harmonic_series_(mathematics)
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checking whether the input series is alternate harmonic series or not
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>>> is_alternate_harmonic_series([1, -1/2, 1/3, -1/4, 1/5])
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True
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>>> is_alternate_harmonic_series([2/5, -2/10, 2/15, -2/20, 2/25])
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True
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>>> is_alternate_harmonic_series([1, 1/2, 1/3, 1/4])
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False
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>>> is_alternate_harmonic_series([1, -1/2, 1/4, -1/8])
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False
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>>> is_alternate_harmonic_series(4)
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Traceback (most recent call last):
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...
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ValueError: Input series is not valid, valid series - [1, 2/3, 2]
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>>> is_alternate_harmonic_series([])
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Traceback (most recent call last):
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...
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ValueError: Input list must be a non empty list
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>>> is_alternate_harmonic_series([0])
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Traceback (most recent call last):
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...
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ValueError: Input series cannot have 0 as an element
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>>> is_alternate_harmonic_series([1,2,0,6])
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Traceback (most recent call last):
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...
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ValueError: Input series cannot have 0 as an element
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"""
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if not isinstance(series, list):
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raise ValueError("Input series is not valid, valid series - [1, 2/3, 2]")
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if len(series) == 0:
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raise ValueError("Input list must be a non empty list")
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if len(series) == 1 and series[0] != 0:
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return True
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receprocal = []
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series_len = len(series)
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for i in range(series_len):
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if series[i] == 0:
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raise ValueError("Input series cannot have 0 as an element")
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receprocal.append(1 / series[i])
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common_diff = abs(receprocal[1]) - abs(receprocal[0])
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for index in range(2, series_len):
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if (
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abs(receprocal[index]) - abs(receprocal[index - 1]) != common_diff
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or receprocal[index] * receprocal[index - 1] >= 0
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):
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return False
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return True
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if __name__ == "__main__":
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import doctest
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doctest.testmod()
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