https://gitlab.com/maximoburrito/advent2022/-/blob/main/src/day18/main.clj I'm actually quite happy with this code for a change. Thankfully the technique suggested by the problem statement turned out to be a good direction...

I got part 1 easily-enough, but I'm getting one more air-pocket than I should when running part-2 on the example data.

It's weird-- I checked it out and the "wrong" air-pocket is in fact surrounded by blocks on all 6 faces.

@U0954HGDQ i like the brutal way to get the (cubic) bounds 😄

Hmmm... from reading reddit, looks like I should be doing a BFS or flood-fill. Think I'll try the BFS first.

on my input it didn’t matter, but i tried expanding the area by a lot and DFS was much much faster. It makes sense — if you want to check if you can reach the edge, try going far in one direction first vs circling around the origin

https://github.com/axelarge/advent-of-code/blob/master/src/advent_of_code/y2022/day18.clj

flood https://github.com/akovantsev/adventofcode/blob/master/src/adventofcode/y2022/day18.clj#L10-L57

p2 3200ms -> 75ms https://github.com/akovantsev/adventofcode/commit/9e88dc04c34ec1b674047b310f3fd44d3aa5f8bd

https://github.com/nbardiuk/adventofcode/blob/master/2022/src/day18.clj

btw, bubbling might be way faster than flood: most of voxels are surface, and the rest would need a several-steps-long search

Probably not an ordinary solution for part 1. It was my first attempt before I realized BFS saves the day

(defn surfaces [[x y z :as coords]]
  (map #(-> #{%1 (mapv + %1 %2)})
       (concat (repeat 3 coords)
               (repeat 3 [(inc x) (inc y) (inc z)]))
       [[ 1  1  0] [ 1  0  1] [ 0  1  1]
        [-1 -1  0] [-1  0 -1] [ 0 -1 -1]]))

(->> (parse large-example)
     (mapcat surfaces)
     (group-by identity)
     (vals)
     (filter #(== (count %) 1))
     (count))

group-by + count can be replaced with frequencies

nice catch

(->> (parse large-example)
     (mapcat surfaces)
     (frequencies)
     (filter #(== (second %) 1))
     (count))

“Unfortunately, you forgot your flint and steel in another dimension.” 🧊

Today was a welcome reprieve from the last couple days: https://github.com/alexalemi/advent/blob/main/2022/clojure/p18.clj

https://github.com/FelipeCortez/advent-of-code/blob/master/2022/18.clj proud of this one 🎉

immediately not proud anymore after seeing your solutions in half the line count

https://github.com/benjamin-asdf/advent-of-code/blob/master/src/Y2022/day18-2.clj

Well my flood fill seems to work so I’m curious what I’m missing for the second part.

I’m also counting surfaces that are “out of bounds”

found it 😞

Day 18 https://github.com/bhauman/advent-of-code-2022/blob/main/src/adv2022/day18/sol.clj

I’m slowly catching up. Wrote a very concise flood function. https://github.com/wevre/advent-of-code/blob/master/src/advent_of_code/2022/day_18_droplets.clj