Advent of Code 2021 starts tonight! But before then, I have one more reflection from last year’s challenge to share. This one is about the day 19 puzzle, which, to be perfectly honest, I did not particularly enjoy. From the puzzle description: The rules for valid messages (the top part of your puzzle input) are numbered and build upon each other. For example: 0: 1 2 1: "a" 2: 1 3 | 3 1 3: "b" Some rules, like 3: "b", simply match a single character (in this case, b). The remaining rules lis...
