Monday, December 1st at 5 a.m. UTC will mark the start of the eleventh incarnation of Advent of Code, a popular programming contest started back in 2015. The author describes Advent of Code (AoC) as "a series of small programming puzzles for a variety of skill sets and skill levels in any programming language you like".
The rules of AoC are quite simple. Starting from December 1st, every day at 5 a.m. UTC a new task is released. The tasks consist of two parts, where second part is revealed after you solve the first part, and it is a continuation and/or variation of the first part. You don't submit your code, just the result of your calculation.
Important change for 2025: From this year on, Advent of Code will feature 12 days of puzzles instead of the traditional 25. Puzzles are still released daily, Dec 1 - Dec 12. More in the official announcement on reddit.
The participation in AoC is free (although, if you like it, consider donating), all you need to do is log in with your Github, Google, Twitter, or Reddit account.
If you have never participated in AoC before or you want to prepare yourself for the start of the competition by solving some tasks, take a look at the previous events. To bring you up to speed, we recommend solving any of the first 5 tasks of any year, as those are usually easier and can be solved relatively fast.
Advent of Code offers private leaderboards. Here is the Nim leaderboard for this year:
We've created a new private leaderboard for 2025 because the existing Nim leaderboards from previous years have many participants who may not be actively using Nim for this event. You can join it by using 5173823-4add4eb1 code on this link.
If you have joined one of the old Nim leaderboards in previous years, you can still find them here:
In this thread you can post links to your AoC repositories, share your solutions, ask for help, discuss the tasks, etc.
People usually share their solutions on r/adventofcode subreddit and we encourage you to share your Nim solutions there too and showcase the beauty of Nim.
If you're sharing your solutions via X, Bluesky, Mastodon or other platforms, use #AdventOfNim hashtag.
You can also use Nim IRC/Gitter/Discord channel (https://discord.gg/nim, #aoc channel) if you have some Nim-related problem, but have in mind that your snippets might contain spoilers for others who haven't solved the task yet - not everybody will be able to solve the tasks at 5 a.m. UTC. Consider waiting at least a couple of hours before asking for help (in that time, try it some more to see if you can solve it by yourself :)).
Have fun!
I'd be up for trying that if there are some fairly simple ones. The nice thing about AoC though is that I know it's fairly easily solveable, I can make pretty accurate estimates for how long I will spend solving them, and when doing them on camera I can spend my time showcasing nice Nim features.
But if you've got a good list of simple issues I'd be down to take a look for sure.
Yeah well:
nim c src/nimony/nimony Hint: mm: orc; threads: on; opt: none (DEBUG BUILD, -d:release generates faster code) 120576 lines; 2.069s; 339.461MiB peakmem;
The main difference is AoC problems are self-contained and you need about 0-3 minutes to understand what needs to be done and not much longer to understand how. With Nim you often don't even have a well-defined problem to start with and the main obstacle is understanding the the bigger system. untangling heaps of sparsely-documented code while trying to sift through git-blame and GH issues to fish out some context nuggets.
This can take days and is a totally different sort of fun.
Hope working on Nimony is much easier due to seemingly more modular approach taken.
I don't think I've ever even made it to day 12! Either way you can find my solutions here
and for additional fun you can browse them from your terminal if ya want:
ssh -p 23231 git.dayl.in -t advent-of-code-2025