I wrote a blog post about this year's Advent of Code. I had a blast and I am already looking forward to 2026! * All my Python solutions were under 1s using pure Python and 100ms with a little help from mypy/scipy • The AoC community is the best ❤️

Anže’s Blog

Advent of Code 2025 🎄

December is the time for Advent of Code, as it has been since 2015, when the first Advent of Code event was published.

I've finished #adventofcode 2025 and this is the first year that I managed to get all solutions under 100ms ⚡ All but two are under 10ms. Not bad for the slowest popular language out there 🐍, although I did have to use numpy a few times.

It has been 15 years since I joined GitHub 😱

New release of adventofcode PyPI package today improves the display of alternative solutions for each day: 1. Slower solutions are no longer counted in totals 2. Slower solutions are dimmed out Why limit yourself to one #adventofcode solution per day? 😆 Happy solving! 🎄

I compared the first 4 #adventofcode solutions on two different CPUs. * Rows with a red background are on 8x Intel(R) Core(TM) i7-10510U CPU @ 1.80GHz. * Rows with a green background are on Apple M3 Max. So if you want to be better at advent of code just get a better CPU? 😆

I wonder how long I'll be able to keep all the days green like this #adventofcode 🟢 Today I learned that you can use None when slicing a list in Python: >>> [1,2,3][:None] [1, 2, 3] Useful to avoid the edge case where [:0] would give an empty list: >>> [1,2,3][:0] []

Just launched version 25.4 of my adventofcode PyPI package! 🚀 25.4 adds a `adventofcode run` command that removes the ugly boilerplate that you had to have in your puzzle files until now! Before: After:

Day 2 of #adventofcode kinda felt easier than day 1 or was it just me? I got to the solution fairly quickly but it was a bit slow. I then spent the next hour optimizing it and managed to make part 1 200x faster and part 2 500x faster 🎉

Day 1 of #adventofcode felt a bit harder than previous day 1 puzzles. It took me way longer to figure out part 2 than I care to admit, but I'm blaming this on my sleepy brain 😅 My code took 1.1ms for both parts without any perf optimizations 🎉 Eleven more to go!

6 hours until the first advent of code puzzle unlocks. Who's going to participate this year? 🎄