This year I took part in the advent of code event. If you’ve never heard about it, I attach tl;dr bellow. Today, I’d like to share my solution for Day 7 problem, because I find it very interesting. In the first half of the post I describe comparison in time complexity of two solutions (programming). In the second half I outline the proof of one solution (math). What is the Advent of Code # For sure you had some kind of advent calendar in the past (or you still have), e.