codility_count_factor_85.rb

require 'prime'

def solution(n)
  primes, powers = n.prime_division.transpose
  exponents = powers.map { |i| (0..i).to_a }
  divisors = exponents.shift.product(*exponents).map do |powers|
    primes.zip(powers).map { |prime, power| prime ** power }.inject(:*)
  end
  result = divisors.sort.map { |div| [div, n / div] }
  return 0 if result.nil?
  result.flatten.uniq.size
end