Solutions to all 500 puzzles from Advent of Code 2015-2024: https://adventofcode.com/

Almost all of this code was written as quickly as possible (about 6-10 hours per year), and never cleaned up after getting the correct answer out of it, so it's pretty horrible.

This was done in Rust, written almost entirely from scratch without the use of third-party libraries (because it's more fun to figure out and understand the algorithms myself), except for a few standard features that would be too hard or too boring to reimplement:

• Commonly used:
  • itertools for collect_vec, permutations, etc
  • peg for parsing the more complicated syntaxes (I also tried lalrpop and pest, but peg worked the best)
  • rayon for easily parallelising some computations, because optimised brute force can be quicker than finding a cleverer algorithm
  • std obviously
• Rarely used:
  • crossbeam for some multithreading
  • fancy-regex for regexes with backrefs
  • md-5, hex for puzzles that require MD5
  • nalgebra for some 2D/3D vectors, when I couldn't be bothered to do all the maths explicitly
  • num for bigint and rational, when brute-forcing and finding i128 isn't big enough
  • serde_json for parsing JSON subsets
  • thiserror for writing a reasonably-generic pathfinding library that was reused in many puzzles