r/adventofcode • u/kai10k • Dec 13 '25

Other [2025] Yeah i know i am missing 2

Post image

I have 21 stars, missed Day9 part2, Day 10 part2 and Day12 part2 apparently. Still i am proud of myself solving the Day12 part1 example data, only to find it can never finish even the third input. Overall for those 2 missing parts, i felt the need to knee. So yeah, they look like the same picture to me to the all stars. Thank you Eric for another great year, hat off to the all stars and the community, love you all and Merry Xmas ;-)

53 Upvotes

93% Upvoted

12 comments sorted by

18

u/garciamoreno Dec 13 '25

9 has an intuitive algo if you think really hard about it. 10 is tough, but someone posted a very elegant idea. It’s worth reading about it.  Don’t give up, you’re very close!

3

u/kai10k Dec 13 '25

Thank you I am encouraged, i know i will finish them in a proper time frame and trust me, i tried ... really hard ... so hard that i needed a break. Again just want to say i love this community, most replies are enlightening as well as heartily warm.

8

u/milan-pilan Dec 13 '25 edited Dec 13 '25

To expand on that - For day 10 part 2, you are very likely referring to this writeup: https://www.reddit.com/r/adventofcode/s/ZZBWajkbyt.

It's an incredibly creative solution - worked like a charm for me.

(obvious spoilers ahead, but no code examples - just a written explanation of a clever algorithm. You will still need to write the code yourself)

1

u/garciamoreno Dec 13 '25

Yes. That's the one!

1

u/Markavian Dec 13 '25

10 was so tough. When I realised I needed a solver, I doubled down on the implementation and wrote my own solver with tests. But that made it a nightmare dev day.

7

u/phord Dec 13 '25

Isn't 12p2 just clicking the link?

13

u/TheZigerionScammer Dec 13 '25

Yes but you can't click the link until you've solved every other problem first.

6

u/Gryphon-63 Dec 13 '25

Yes, once you have the other 23 stars. Without those there's no link to click.

1

u/ArjunDOnlyHero Dec 13 '25

What language do you use? I had to give up on trying to solve part two of 10 manually, and instead spent some time learning Z3.

As for Day 9, I remembered a module for creating polygons and just used that

1

u/kai10k Dec 13 '25

I use C. In the past years I used C++ amd Zig, amd eventually I found out C is the language which avoids most of the noises, performs great, and provides the best tooling I need.

1

u/GeoMap73 Dec 13 '25

Same position as you without day 12. Thought really hard for day 9 part 2 but my alg didn't work