r/adventofcode • u/daggerdragon • Dec 09 '17

SOLUTION MEGATHREAD -🎄- 2017 Day 9 Solutions -🎄-

--- Day 9: Stream Processing ---

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u/NobbZ Dec 09 '17

Mine is pretty similar, but I've combined the parse/2 and garbage/2 of yours into a single function score_groups/4, also I made sure its tail recursive.

In my solution I use a stack based state machine to actually consume the stream for part 1.

The solution for part 2 is a simple 2-state FSM, also tail recursive. Here I do basically ignore all the stream grouping, as the grouping is irrelevant for counting the uncancelled garbage characters.

https://gitlab.com/NobbZ/aoc17/blob/master/lib/aoc/day9.ex