2021-advent-of-code VS AdventOfCode

Here is the recursive function (the heart of the algorithm). Here is the full code with more comments.

Rust

Just a basic BFS. My part 2 ran in 1.77 seconds.

Here's my solution. It's a bit of a janky script.

Yet another Python solution to part 2. My Python code isn't the best but I haven't seen many solutions that detect cycles programmatically.

There's nothing particularly nice about my Python solution but in case anyone's interested here it is. I find all points' shortest paths using floodfill and a loop because I couldn't recall Floyd-Warshall. And then it's a DFS, branching every turn when the human or elephant can make a choice to move to another valve and open it. Debugging was tricky.

You can check my solutions from last year https://github.com/WilliamLP/AdventOfCode/tree/master/2021 I made it up to day 14 / 17 and used that WITH RECURSIVE / UNNEST / ARRAY_AGG pattern a lot.

I got there, but math! It took a few hours, more along the lines of a weekend project than a quick puzzle! The hardest part is working with the 24 orientations I think. I needed to dust off a little bit of linear algebra and used matrices. There are 6 permutations of the 3 coordinates, and 8 flips (+- on each axis). Composing those gives 48 transformations but half of them are the wrong chirality (mirror image) so we want only the half with determinant equal one. After that it's just a bunch of picky loops and debugging. https://github.com/WilliamLP/AdventOfCode/blob/master/2021/day19.py