> So that first one is about solving an advent of code problem cleverly. Ah but it's not just about that, it's also about figuring out what problems can be fit

> So that first one is about solving an advent of code problem cleverly. Ah but it's not just about that, it's also about figuring out what problems can be fit into bit twiddling, knowledge about bitwise operation (especially that xor is self-reversing so it handles set/unset as well as pairs), and the ability to reduce effective complexity. I agree it's not useful if you're currently on a quest > to get better at writing code that's easy to read and change but thinking of it as "solving an advent of code problem cleverly" misses most of the information.