The day 13 puzzle from last year’s Advent of Code was the first one that left me really flummoxed. Part 1 (the warm-up) was straight-forward enough, but part 2 required left me feeling like there was some really useful math that I didn’t know. The puzzle was about a set of buses that all take different amounts of time to complete their routes, and keep looping around forever. After getting past all the flavor text, part 2 of the puzzle boiled down to this: given a set of tuples \( \{(k_i,...
