General tip about AoC problems: a favorite “part 2” tactic is to expand the problem in a way that makes inefficient solutions intractable. For instance, the solution for my day 5 part 2 was ~15 million so locations would likely be LARGE
There’s another one later on this year where the straightforward “generate and count” approach fails even more spectacularly - with my input, a counting approach would have taken quite a while to count to 15 trillion!
IMO this is the best part of AoC, since usually it takes months / years of “production” use to find out an algorithm is inefficient.
