I cleaned up all my of AoC (Advent of Code) 2025 solutions, refactored many of the utilities I had to write as reusable libraries, re-tested Day 1 (but nothing else). here it is if you’re curious! This is written in mu, my own language I built as a self-hosted minimal compiler/vm with very few types and builtins.

https://git.mills.io/prologic/aoc2025


#4fadlsa

(#te6p5oa) @movq@www.uninformativ.de I shrank Day 9 Part 2 from ā€œcover the whole mapā€ to ā€œonly track the interesting lines.ā€ By compressing coordinates to just the unique x/y breakpoints, the grid got tiny. I still flood-fill and do the corner-pair checks, but now on that compact grid with weighted prefix sums for instant rectangle checks. Result: far less RAM, way less CPU, same correct answer.


#2qqbk5a

Day 9 also required some optimizations, if you aren’t careful, you end up with really inefficient algorithms with time/memory complexity beyond what a typical machine has 🤣


#te6p5oa

Day 7 was pretty tough, I initially ended up implementing an exponential in both time and memory solution that I killed because it was eating all the resources on my Mac Studio, and this poor little machine only has 32GB of memory (I stopped it at 118GB of memory, swapping badly!), This is what I ended up doing before/after:

  • Before: Time O(2^k Ā· L), memory O(2^k), where k is the number of splitters along a reachable path and L is path length. Exponential in k.
  • After: Time O(RĀ·C) (or O(RĀ·C + s) with s split events), memory OĀ©, where R = rows, C = columns. Polynomial/linear in grid size.

#6qxqjma

(#4bg5k7a) Bought more cheap slot plates (with bad reviews and people complaining about the pin order, because I could’nt find a product without such reviews), but those are simply correct now and just work. 🤪


#73q3jqa

I’m having to write my own functions like this in mu just to solve AoC puzzles :D

fn pow10(k) {
    p := 1
    i := 0
    while i < k {
        p = p * 10
        i = i + 1
    }
    return p
}

#i6myoaq

I’m seeing crashes in the 3D subsystem. (Gallium? Glamor? Whatever other Mesa thing they have? No idea.) In the logs I find this:

malloc(): unaligned tcache chunk detected

And that’s why I still care about Rust and want to learn more about it, even though it’s giving me so much headache and I’ve given up so many times. Because Rust currently seems to be the only popular systems programming language that tries to eliminate these error classes.

And of course ā€œthe Rust experimentā€ in the Linux kernel has recently been concluded as ā€œsuccessfulā€, so that alone is reason enough for me:

https://lwn.net/Articles/1049831/


#zfqkd4q

(#ruoopea) > That’s the right answer! You are one gold star closer to decorating the North Pole. [Continue to Part Two]

Whoo! Making progress! With AoC 2025 solutions implemented in my own toy language 🤣


#jbg2wfq

(#ruoopea) Ahh that’s because I forgot to call main() at the end of the source file. mu is a bit of a dynamic programming language, mix of Go(ish) and Python(ish).

$ ./bin/mu examples/aoc2025/day1.mu 
Execution failed: undefined variable readline

#arn73ea

Come back from my trip, run my AoC 2025 Day 1 solution in my own language (mu) and find it didn’t run correctly 🤣 Ooops!

$ ./bin/mu examples/aoc2025/day1.mu
closure[0x140001544e0]

#ruoopea

(#ftqfrta) Alright, Advent of Code is over:

https://www.uninformativ.de/blog/postings/2025-12-12/0/POSTING-en.html

It’s been quite the time sink, especially with the DOS games on top, but it was fun. 🄳

In case you’re wondering: All puzzles (except for part 2 of day 10) were doable in Python 1 on SuSE Linux 6.4 and ran in a finite time on the Pentium 133. Puzzle 10/2 might have been doable as well if I had better education. 🤣


#n3gzxaa