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.
This enables the binary to be invoked from anywhere and still run on the default input set, as well as being more portable/shareable which can help with performance comparisons between machines. Files are still supported if they exist.
