Project Euler 70

problem70.rb

def phi p1, p2
  (p1-1)*(p2-1)
end

def find 
  min = [0,2]
  lst = prime_sieve 5000
  lst.keep_if{|x| x > 2000}
  lst.reverse_each do |p1|
    lst.reverse_each do |p2|
      if p1*p2 <= 10**7
        n = p1*p2
        m = phi p1, p2.to_f
	if min[1] > n/m && permutation?(n, m.to_i)
	  min = [n,n/m]
        end
      end
    end
  end
  min[0]
end