advent-of-code VS advent-of-code-2020

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.

I'm new to Scala so would welcome pointers on more idiomatic etc ways of doing things. Here's my AOC 2020 repo