mirror of
https://github.com/TheAlgorithms/Ruby
synced 2024-12-30 22:24:11 +01:00
29 lines
679 B
Ruby
29 lines
679 B
Ruby
# frozen_string_literal: true
|
|
|
|
# The prime factors of 13195 are 5, 7, 13 and 29.
|
|
# What is the largest prime factor of the number 600851475143
|
|
|
|
# find all factors of the given number
|
|
def get_factors(number)
|
|
factors = []
|
|
(1..Math.sqrt(number).to_i).each do |num|
|
|
if (number % num).zero?
|
|
factors << num
|
|
factors << number / num
|
|
end
|
|
end
|
|
factors
|
|
end
|
|
|
|
# determine if a given number is a prime number
|
|
def prime?(number)
|
|
get_factors(number).length == 2
|
|
end
|
|
|
|
# find the largest prime
|
|
def largest_prime_factor(number)
|
|
prime_factors = get_factors(number).select { |factor| prime?(factor) }
|
|
prime_factors.max
|
|
end
|
|
|
|
puts largest_prime_factor(600_851_475_143)
|