advent-of-code VS advent-of-code

I didn't realize Haskell had that. I wrote a similar Scala library for 2022 Day 15 that's basically the encapsulated equivalent of a [Range a], but I really like the API of Haskell's library. Especially Haskell always handles infinite sequences well.

[LANGUAGE: Scala] GitHub

Here's mine. Most of it I wrote in prior years, but refined this year. To account for problem-specific details, the functions are very generic and higher-order. It has a handful of well-known algorithms like A* and Floyd-Warshall, some handy data structures like circular buffers and intervals, and some type classes that are useful for parsing puzzle input.

Scala 30ms + 70ms

Scala 6.5 seconds.

Scala

I wrote an immutable A* in Scala a few years ago. It's not too bad if you have immutable hash maps and an immutable priority queue. Comes in handy for a lot of puzzles.

Last year I made myself an input parsing library that was really nice for this problem. I just create a Pair class with 4 number members, then ask for a List[Pair] and it knows what to do. My solution.

I implemented my own using a pairing heap. It sped up my immutable A* considerably, but I was just using minBy on a List before that. Inserts are amortized O(1) and delete-mins are O(log n).

This year I'm creating a Scala library to make it easier. I specify a type like List[Int] and it summons the correct type classes to parse it into that format for me.

30 lines of code, lightly golfed, but mostly pretty readable.

This solution in Perl 5 provides an ASCII animation in your terminal as it finds the solution. You need a fairly wide terminal for it to work. (The input map is 64 cells wide and the output uses 3 characters per cell, so you'll need a terminal width of at least 64×3 = 192 characters.)