aoc_kotlin VS AdventOfCode

[LANGUAGE: Kotlin] 757 / 504 Code

Link to solution

code

Kotlin 171/147 and a more general solution

Kotlin 1948/1806

Uses some collection helper functions and a tiny matrix math library.

Code itself is here: https://github.com/madisp/aoc_kotlin/blob/main/src/main/kotlin/day6_fast.kt

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