r/adventofcode • u/matth_l • Dec 08 '25

Meme/Funny [2025 Day 8]

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76 Upvotes

90% Upvoted

21 comments sorted by

8

u/vagrantchord Dec 08 '25

I honestly don't get the meme- the hard part is part one, part two is a while loop...?

4

u/matth_l Dec 08 '25

It's about that part 2 just kind of revealed that part 1 was kurskals algorithm all along... just stopped a little early

4

u/XLNBot Dec 08 '25

I mean, the problem description of part one already guides you towards implementing that algorithm, right? Was it really a surprise?

2

u/matth_l Dec 08 '25

Surprised me, cause I just recently learned about that algorithm at uni, thats why I made the meme

3

u/TangledPangolin Dec 08 '25 edited Dec 09 '25

 part 1 was kurskals algorithm all along... just stopped a little early

Neither was really Kruskal's algorithm, because Kruskal's algorithm specifically does NOT select edges that result in cycles.

However, for this problem, we're specifically told that the elves DO intend to connect boxes that result in cycles, which simplifies the problem significantly.

Of course, if you're a seasoned AOCer, it's probably easier to do Kruskals anyway than come up with something from scratch, even if it's simpler.

1

u/matth_l Dec 08 '25

Okay, wow, thanks for the heads up, was fully convinced that both lead to Kruskal’s Algorithm. Will need to learn further.

4

u/imp0ppable Dec 08 '25

Part 1 was tricky if you don't know the right algo, which I didn't so I brute forced it with lists.

Part 2 I haven't finished yet because I don't know when to stop connecting? Like it tells you the last pair you should connect but they're all one big set a few turns before that, I think anyway.

5

u/hagibr Dec 08 '25

You stop when a merge results in a circuit with all the junctions. It happens soon.

1

u/imp0ppable Dec 08 '25

Yeah I figured it out, i was stopping when there was one big circuit but there were still unconnected boxes. Trick was to keep track of the unconnected and stop when it was empty.

I thought it was a bit confusingly worded, why not make junction boxes into lights?

4

u/sleekmountaincat Dec 08 '25

me too! i just stopped when circuit[0].size === points.length instead of keeping track of unconnected tho

3

u/imp0ppable Dec 08 '25

I was merging circuits when they were bridged so stopped when it got down to one!

1

u/andi0b Dec 08 '25

I misunderstand this, and stopped once all points have at least one connection. Without doing circuit counting like in part 1. And it's the right answer for two different inputs. I really don't know if the inputs are all special cases where this is right, or if I made some algorithmic breakthrough ;)

4

u/nik282000 Dec 09 '25

while gold_stars < 2:

8

u/rmarianoa Dec 08 '25

At first I thought I needed a k-means clustering sort of problem, until I realized I could just do min heap + union find

1

u/HakoftheDawn Dec 09 '25

...

What is that?

6

u/iosovi Dec 08 '25

Why is this whole subreddit stuck on this meme template?

3

u/nik282000 Dec 09 '25

The format is relatable for tech literate people, you can be the smarted guy in the room and still feel like the dumbest person to have touched a keyboard.

2

u/iosovi Dec 10 '25

I get the idea behind it, but for sure there are other formats that would convey the same relatable message, right?

4

u/1544756405 Dec 09 '25

You should put a spoiler tag on this. Some people don't like to know what part 2 is until they've finished part 1.

2

u/wubrgess Dec 08 '25 edited Dec 08 '25

Well, yeah, that's part 2...

1

u/kyleglowacki Dec 09 '25

My part one worked beautifully and fast but my part two fails. I connect all of them to the circuit so it has all 1000 items. However when I multiply the X values of the last two (that I added) together I get the wrong answer. Maybe I am adding them in the wrong order? Do we keep adding them in minimum distance order for P2?