mirror of
https://github.com/TheAlgorithms/Ruby
synced 2024-12-28 22:24:14 +01:00
29 lines
679 B
Ruby
29 lines
679 B
Ruby
# frozen_string_literal: true
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# The prime factors of 13195 are 5, 7, 13 and 29.
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# What is the largest prime factor of the number 600851475143
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# find all factors of the given number
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def get_factors(number)
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factors = []
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(1..Math.sqrt(number).to_i).each do |num|
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if (number % num).zero?
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factors << num
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factors << number / num
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end
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end
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factors
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end
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# determine if a given number is a prime number
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def prime?(number)
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get_factors(number).length == 2
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end
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# find the largest prime
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def largest_prime_factor(number)
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prime_factors = get_factors(number).select { |factor| prime?(factor) }
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prime_factors.max
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end
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puts largest_prime_factor(600_851_475_143)
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