@anze3db Nice, I also did mine in Python but didn't optimize it for speed. I only beat you on day 7 (~0.5ms, but that's for both parts at the same time). I looked at your code. Using a dict for the beams and recreating it every loop is probably costing you some clock cycles. I think you can get it close to 1ms. :) https://github.com/goncalomb/advent-of-code