Fast Parse VS advent-of-code

Perhaps use Li Haoyi's fastparse instead? https://github.com/com-lihaoyi/fastparse

You might want to adapt Li Haoyi’s XML parser for fastparse.

Mostly a mess of pattern matching. I really need to make some generic tree utilities. Haven't been able to find a decent parser combinator that works in Scala 3 (I usually use fastparse which depends heavily on Scala 2 macros, and scala-parser-combinators works in Scala 3, but I've had a lot of trouble getting it to not be too greedy), so I used the state monad from cats to parse at the bottom of the file, which I think turned out fairly nice.

Agreed! I would say that parser combinators are the sweet spot and the right choice in most cases.

Scala has them as well, e.g.: https://com-lihaoyi.github.io/fastparse/

And the good thing is, you don't have to learn a completely new language/syntax, you can use the host language's syntax and you have full IDE support as well.

For a full write-up, see this repo, and for a non-annotated solution, see:

Otherwise, the main way I solved this was with a flat list of tokens rather than a truly nested structure. This was very similar to last year's Day 18, which I also solved in a similar manner.

Code can be found in this repo.

code

First 2D one! Got to reuse my InfiniteGrid class, which made this much easier.

Mine only took about 2 minutes when I originally recorded it. I've since added some optimizations to my Intcode computer, and re-running my original program with the optimized computer now runs in about 45 seconds. 😁

Here is my solution in JS, which also has a long comment explaining the main iterative loop.

Your solution is very similar to mine, and I too found that using an Array of a set size was way faster than an ordinary Object. I believe it has to resizing the array / object.

Main code for part two here, with comments, and full code for all parts found here.