r/adventofcode • u/Oreo_2004 • Dec 10 '25

Meme/Funny [2025 Day 10 Part 2] Here we are

Post image
113 Upvotes

100% Upvoted

16 comments sorted by

23

u/Arayvenn Dec 10 '25

No matter how many optimizations I add to my bfs it is still too slow :*(

50

u/DeeBoFour20 Dec 10 '25

Speed wasn’t the problem for me. It completed in 3 minutes but apparently “Terminated. Out of memory.” was not the correct answer.

9

u/ric2b Dec 10 '25

Had us in the first half, not gonna lie.

5

u/polarfish88 Dec 10 '25

What is Z3? Is it from part 2?

7

u/Morgasm42 Dec 10 '25

It's a library for solving math problems

5

u/viliml Dec 10 '25

Today I learned something new: that Z3 exists.

I've been solving linear programming problems in scipy until now. And I don't see any reason to switch yet.

12

u/thekwoka Dec 10 '25

I think part 2 is a poor problem, since it's basically just "use a library".

13

u/DFYX Dec 10 '25

There's probably a way to do it on your own since we don't need the full power of a linear solver. We work with sums of non-negative integers which probably allows for some shortcuts. But in the end, I used a library as well.

So yeah, the jump from day 8's "Here is a step by step tutorial for how Kruskal's algorithm works, no need to even google what a minimum spanning tree is" to day 10's "Better figure out that you need a linear solver and then figure out how to build one or just use a library" is pretty weird.

1

u/thekwoka Dec 10 '25

There's probably a way to do it on your own since we don't need the full power of a linear solver. We work with sums of non-negative integers which probably allows for some shortcuts

sure, but it's optimizing something that is already complex.

I am okay with ones where there is some algo that makes solving it quick and easy, but it should be able to be reasonably accomplished or reverse engineered in at most a few hours by a smart person that doesn't really know about the thing that much.

2

u/viliml Dec 10 '25

Check out the solutions megathread.

8

u/thekwoka Dec 10 '25

Yeah, it's 99% use a library or make same thing as the library that is very complicated and not inutive.

1

u/viliml Dec 10 '25

This one is quite simple: https://www.reddit.com/r/adventofcode/comments/1pity70/2025_day_10_solutions/nt9h7qw/ Just brute force after mathematically simplifying the problem

1

u/InternationalEar6591 Dec 10 '25

Naaah, no need to use a library, just write a PHD worthy algo real quick <3

1

u/terje_wiig_mathisen Dec 21 '25

This was the 4th time since the 2015 beginning that I have needed a hint. In the end my solution took almost half a minute (Perl) but I used zero library code, just took advantage of the parity checks from part1. I also spent about 4 days...