I am not completely happy with this data structure, but it's functional enough. I wanted to implement comparers and equality overrides for the classes to make part 2 shorter, but it would have come at the cost of a bunch of boilerplate code, so whatever.
This is quite slow, at least for part 2 (and part 1 is slower than I want it to be, event parse takes longer than I thought it should). I need a better approach to the second part. Probably need to mark all nodes' distances from the goal point instead of one-by-one plotting a path from each possible start to the end, but that requires an adjustment to how I'm building the graph in the first place.
This is ugly. I probably should've vec2'd this, made smarter move and follow logic that isn't a series of 'if's, and found a smarter way to calculate distance than my hackneyed vector distance, but it totally works so I'm rolling with it.
I'm sure there's a cleaner way to search in four directions rather than manually running each loop like this, but I didn't want to mess with genericizing it just yet.
A Deep Copy and a double-ended queue would have made this day much easier. I should add those. (Having trouble finding a generic deep copy that works in .net 6, though...I opted to rewrite my original List<List<char>> solution into List<string> in lieu of a deep copy so I wouldn't have to parse the input all over again.)
This is an ugly, kind-of-brute-force solution. I'm not proud of it, but it works and got me top 1000 on both parts.
I also changed the "which day to run if no day is specified" to just always choose the highest numbered day.
