As always, I'm doing Advent of Code this year. This year, I'm doing it in CPP2 (Herb Sutter's C++ experiment). You can find it at https://github.com/hsutter/cppfront but I'm actually using my own version with JohelEGP's module support in place -- https://github.com/threeifbyair/cppfront . I'm using it both to learn and think about safe C++, and to provide some fresh eyes on cppfront. (And boy, do I have OPINIONS.)
You'll also find my Advent 2023 repo growing with CPP2 code as I do the same thing with other puzzles.
If you want to reproduce what I'm doing (as of October 2025!), I have CMake 3.30 running on Ubuntu 25.10, using a version of Boost 1.89 compiled with the Bloomberg P2996 version of clang and libc++.
Note that Advent of Code frowns on including input files in public repos; the input files that were previously present have been replaced with encrypted files.