this post was submitted on 10 Dec 2024
6 points (100.0% liked)

NotAwfulTech

386 readers
4 users here now

a community for posting cool tech news you don’t want to sneer at

non-awfulness of tech is not required or else we wouldn’t have any posts

founded 1 year ago
MODERATORS
[email protected]
6
Advent of Code 2024 Week 2: this time it's all grids, all the time (awful.systems)
submitted 1 week ago by [email protected] to c/[email protected]
24 comments fedilink hide all child comments
 

The previous thread has fallen off the front page, feel free to use this for discussions on current problems

Rules: no spoilers, use the handy dandy spoiler preset to mark discussions as spoilers

you are viewing a single comment's thread
view the rest of the comments
[–] [email protected] 2 points 1 week ago* (last edited 1 week ago) (3 children)

Day 13, day 13 of shirking other responsibilities.

p1Ok. So, I overthought this a little. Ultimately, this problem boils down to solving a system of 2 linear equations aka inverting a matrix.

Of course, anyone who has done undergraduate linear algebra knows to look to the determinant in case some shit goes down. For the general problem space, a zero determinant means that one equation is just a multiple of the other. A solution could still exist in this case. Consider:

a => x+1, y+1
b => x+2, y+2
x = 4, y = 4 (answer: 2 tokens)

The following has no solution:

a => x+2, y+2
b => x+4, y+4
x = 3, y = 3

I thought of all this, and instead of coding the solution, I just checked if any such cases were in my input. There weren't, and I was home free.

p2No real changes to the solution to p1 aside from the new targets. I wasn't sure if 64 bit ints were big enough to fit the numbers so I changed my code to use big ints.

I'm looking at my code again and I'm pretty sure that was all unnecessary.

[–] [email protected] 3 points 1 week ago* (last edited 1 week ago) (1 children)

I liked day 13, a bit easy but in the right way.

Edit:

SpoilersAlthough saying "minimum" was a bit evil when all of the systems had exactly 1 solution (not necessarily in ℕ^2), I wonder if it's puzzle trickiness, anti-LLM (and unfortunate non comp-sci souls) trickiness or if the puzzle was maybe scaled down from a version where there are more solutions.

[–] [email protected] 2 points 1 week ago

spoilerGiven the lack of edge cases, I feel the latter possibility is strong. I'm just glad it was easy!

load more comments (1 replies)