Project Euler 37

gistfile1.rb

#!/usr/bin/ruby
require 'prime'
p=Prime::EratosthenesGenerator.new
a=[];h={}
h[p.next]=1;h[p.next]=1;h[p.next]=1;h[p.next]=1
while true do
	e=p.next
	h[e]=1
	s=e.to_s
	if (s.length-1).times{|i|
		if !h[s[0,i+1].to_i]||!h[s[i+1,s.length-i-1].to_i] then break end
	} then a.push(e) end
	if a.length==11 then break end
end
p a.reduce(&:+)