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50 lines
1.3 KiB
Python
50 lines
1.3 KiB
Python
"""
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== Hexagonal Number ==
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The nth hexagonal number hn is the number of distinct dots
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in a pattern of dots consisting of the outlines of regular
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hexagons with sides up to n dots, when the hexagons are
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overlaid so that they share one vertex.
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https://en.wikipedia.org/wiki/Hexagonal_number
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"""
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# Author : Akshay Dubey (https://github.com/itsAkshayDubey)
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def hexagonal(number: int) -> int:
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"""
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:param number: nth hexagonal number to calculate
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:return: the nth hexagonal number
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Note: A hexagonal number is only defined for positive integers
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>>> hexagonal(4)
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28
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>>> hexagonal(11)
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231
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>>> hexagonal(22)
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946
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>>> hexagonal(0)
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Traceback (most recent call last):
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...
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ValueError: Input must be a positive integer
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>>> hexagonal(-1)
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Traceback (most recent call last):
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...
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ValueError: Input must be a positive integer
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>>> hexagonal(11.0)
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Traceback (most recent call last):
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...
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TypeError: Input value of [number=11.0] must be an integer
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"""
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if not isinstance(number, int):
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msg = f"Input value of [number={number}] must be an integer"
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raise TypeError(msg)
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if number < 1:
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raise ValueError("Input must be a positive integer")
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return number * (2 * number - 1)
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if __name__ == "__main__":
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import doctest
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doctest.testmod()
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