euler12

gistfile1.rb

#!/usr/bin/env ruby

def numDivisors(x)
    factors = 0
    (2..x).take(Math.sqrt(x).to_i + 1).each do |u|
        if x % u == 0
            factors += 2
        end
    end
    factors += 2
    return factors
end

count = 1
tri = 0
loop do
    tri = (1..count).inject(:+) #triangle number
    break if numDivisors(tri) >= 500
    count = count + 1
end
puts "First triangle number to have 500 factors is #{tri}"