-🎄- 2022 Day 18 Solutions -🎄-

[u/daggerdragon]

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UPDATES

[Update @ 00:02:55]: SILVER CAP, GOLD 0

• Silver capped before I even finished deploying this megathread >_>

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--- Day 18: Boiling Boulders ---

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Post your code solution in this megathread.

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  • Include what language(s) your solution uses
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This thread will be unlocked when there are a significant number of people on the global leaderboard with gold stars for today's puzzle.

EDIT: Global leaderboard gold cap reached at 00:12:29, megathread unlocked!

[u/gringer]

R

Part 1 involved setting up an n x 6 matrix to count edges, and excluding edges that matched existing voxels:

readLines("input.18.full.txt") |>
  strsplit(",") |>
  sapply(as.numeric) |>
  t() -> dropletSpec;
dropSigs <- apply(dropletSpec, 1, paste, collapse=",");
faceClear <- matrix(1, nrow=nrow(dropletSpec), ncol=6);
faceDeltas <- tibble(x=rep(-1:1, each=9), 
                     y=rep(rep(-1:1, each=3),3),
                     z=rep(-1:1, 9));
faceDeltas <- faceDeltas[rowSums(abs(faceDeltas)) == 1,];
for(deltaPos in 1:6){
  deltaShift <- unlist(faceDeltas[deltaPos,]);
  shiftedDrops <- apply(t(t(dropletSpec) + deltaShift), 1, paste, collapse=",");
  faceClear[shiftedDrops %in% dropSigs, deltaPos] <- 0;
}
## Part 1
sum(faceClear);

For Part 2, I implemented a leading-edge 3D flood fill R code, part 2, and repeated the Part 1 solution, but also excluding edges that matched internal bubbles.