advent-code-2021 VS advent-2021

(physicist here) see lines 5-12 of my solution, where I use some numpy and nested for-loops to generate all 3x3 permutation matrices with signs flipped and determinant +1. There turns out to be exactly 24 of these, and they are the right ones.

Rust https://github.com/Crazytieguy/advent-2021/blob/master/src/bin/day22/main.rs Imagining the geometry of this was very tricky for me. For a while I contemplated if calculating the intersection of each pair of cuboids would give me enough information to know how many cubes are on at the end, and finally decided that I would also have to calculate the intersections of those and so on, so I gave up. Instead I decided that my state will be a vector of cuboids that are garuanteed to be non overlapping, and on each command I would subtract the current cuboid from each of these non overlapping cuboids (leaving 1 to 6 cuboids depending on intersection), and finally either add in the current cuboid (for on command) or leave it out (for off).