Day 18 part 1 solution

...sort of. It works, but it takes a lot longer than I'd like on real input. I optimized it with some memoization, but it's still far too slow to be the intended solution. I finished my actual input in over 3 minutes on my macbook m1 (...with the right answer, at least).

This solution as-is isn't really going to fly for part 2, though, so I'm probably going to have to re-do it either way.

inputs/18p.txt

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inputs/18s1.txt

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inputs/18s2.txt

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inputs/18s3.txt

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inputs/18s4.txt

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inputs/18s6.txt

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inputs/18s7.txt

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inputs/18s8.txt

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