TheAlgorithms-Python

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"""
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Problem 20: https://projecteuler.net/problem=20
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n! means n × (n − 1) × ... × 3 × 2 × 1
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For example, 10! = 10 × 9 × ... × 3 × 2 × 1 = 3628800,
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and the sum of the digits in the number 10! is 3 + 6 + 2 + 8 + 8 + 0 + 0 = 27.
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Find the sum of the digits in the number 100!
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"""
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from math import factorial
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def solution(num: int = 100) -> int:
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    """Returns the sum of the digits in the factorial of num
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    >>> solution(1000)
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    10539
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    >>> solution(200)
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    1404
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    >>> solution(100)
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    648
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    >>> solution(50)
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    216
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    >>> solution(10)
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    27
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    >>> solution(5)
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    3
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    >>> solution(3)
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    6
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    >>> solution(2)
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    2
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    >>> solution(1)
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    1
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    >>> solution(0)
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    1
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    """
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    return sum(map(int, str(factorial(num))))
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if __name__ == "__main__":
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    print(solution(int(input("Enter the Number: ").strip())))
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