I might have broken the one second guideline a little

My first solution was going to run out of memory, my second: is still running just in case.

I thought it would be a long-runner, but I also guessed that getting to a better solution would take a while, so I set it off and it did eventually return an answer before I could even plan out a solution that might improve things. Who needs algorithms when you've got Moore's law.

My first version ran for about 90 minutes. My second version, for about 45 seconds. I'm sure there's more optimization to be done, but that was good enough for me :)

I coming a bit from behind, just did this question

part1 test answer is 35 (0.00 seconds)

part1 answer is 3374647 (0.10 seconds)

part2 test answer is 46 (0.00 seconds)

part2 answer is 6082852 (0.34 seconds)

interval arithmetics bitch