One of the most difficult problems in NAQ 2024 is Balatro with a recorded 5 solves. I attempted and failed to solve the problem during the contest, and found that my solution differed quite a bit from the intended solution (and also got TLE'ed). I spent quite a bit of my time just trying to speed up my solution, which I found to be interesting.
https://zhtluo.com/cp/constant-optimization-and-cheesing-through-naq.html