10 reviews
Not intuitive to me. Needed a few tries to understand the trick, then got it. Good one. Deserves maybe a 3 rather than a 2? My 1st try was miles away, but soon, I got it right. Good level! A lot of tricks here, had to think a bit. Very nice use of this pattern. Makes you question where the optimizations could be at each step. Just a little inelegant overall, though. 
