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https://github.com/TheAlgorithms/Ruby
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18 lines
523 B
Ruby
18 lines
523 B
Ruby
# frozen_string_literal: true
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# n! means n x (n - 1) x ... x 3 x 2 x 1
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# For example, 10! = 10 x 9 x ... x 3 x 2 x 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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# method to calculate factorial of a number
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def factorial(number)
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number.downto(1).reduce(:*)
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end
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# fetch digits of factorial of `number` and find
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# sum of all those digits, and prints the result on the console
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number = 100
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puts factorial(number).digits.sum
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