I'll be doing AoC in C this year. And I've decided to do that every year as I enjoy doing it in C and trying to get the entire calendar, all 50 parts to run in less than one second on a single core, which it turns out is quite doable, but only with a much deeper understanding of the problems. I end up learning a lot more computer science this way.
I also like it since I don't do any work or even side projects in C these days, and so it's nice to keep my C chops up to scratch.
Nice! I’m writing in C this year too, although I’m very much a beginner in C.
What kinds of optimisations have you had to do? Are you hosting your code anywhere?
I've used it to write some Python code that mimics upset recovery procedures that we teach human pilots. It's quite fun putting an aircraft in a tricky position and then seeing your code recover it nicely to straight and level flight. (Or seeing your code roll it over and fly it into the ground if you got the math wrong :-))