31 lines
635 B
Python
31 lines
635 B
Python
#!/usr/bin/env python3
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# n! means n × (n − 1) × ... × 3 × 2 × 1
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#
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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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#
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# Find the sum of the digits in the number 100!
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from math import factorial
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from projecteuler import timing
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@timing
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def p020() -> None:
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# Calculate the factorial, convert the result to string and sum the digits.
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n = str(factorial(100))
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_sum = 0
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for i in n:
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_sum = _sum + int(i)
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print('Project Euler, Problem 20')
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print(f'Answer: {_sum}')
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if __name__ == '__main__':
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p020()
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