TheAlgorithms-Python

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"""
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Author  : Alexander Pantyukhin
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Date    : November 1, 2022
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Task:
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Given a positive int number. Return True if this number is power of 2
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or False otherwise.
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Implementation notes: Use bit manipulation.
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For example if the number is the power of two it's bits representation:
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n     = 0..100..00
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n - 1 = 0..011..11
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n & (n - 1) - no intersections = 0
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"""
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def is_power_of_two(number: int) -> bool:
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    """
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    Return True if this number is power of 2 or False otherwise.
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    >>> is_power_of_two(0)
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    True
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    >>> is_power_of_two(1)
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    True
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    >>> is_power_of_two(2)
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    True
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    >>> is_power_of_two(4)
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    True
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    >>> is_power_of_two(6)
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    False
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    >>> is_power_of_two(8)
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    True
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    >>> is_power_of_two(17)
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    False
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    >>> is_power_of_two(-1)
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    Traceback (most recent call last):
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        ...
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    ValueError: number must not be negative
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    >>> is_power_of_two(1.2)
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    Traceback (most recent call last):
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        ...
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    TypeError: unsupported operand type(s) for &: 'float' and 'float'
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    # Test all powers of 2 from 0 to 10,000
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    >>> all(is_power_of_two(int(2 ** i)) for i in range(10000))
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    True
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    """
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    if number < 0:
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        raise ValueError("number must not be negative")
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    return number & (number - 1) == 0
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if __name__ == "__main__":
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    import doctest
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    doctest.testmod()
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