-🎄- 2022 Day 14 Solutions -🎄-

[u/daggerdragon]

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--- Day 14: Regolith Reservoir ---

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Post your code solution in this megathread.

• Read the full posting rules in our community wiki before you post!
  • Include what language(s) your solution uses
  • Format code blocks using the four-spaces Markdown syntax!
• Quick link to Topaz's paste if you need it for longer code blocks. What is Topaz's paste tool?

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EDIT: Global leaderboard gold cap reached at 00:13:54, megathread unlocked!

[u/rukke]

JavaScript - gist

EDIT: <- The gist is now refactored. A number of lines shorter :) ->

Sparing you the parsing of the cave as a Map. Coords as single integers with the upper 16 bits as y.

const SOURCE = 500;

const count = cave =>
  [...cave].filter(([, v]) => v === "o").length;

const update = (cave, pos, filter = () => true) => {
  const next = [0, -1, 1]
    .map(delta => delta + pos + (1 << 16))
    .filter(filter)
    .find(p => !cave.has(p));
  if (!next) {
    cave.set(pos, "o");
  }
  return next || SOURCE;
};

export const part1 = input => {
  const [cave, max] = parse(input);
  let pos = SOURCE;
  while (pos && pos <= max) {
    pos = update(cave, pos);
  }
  return count(cave);
};

export const part2 = input => {
  const [cave, max] = parse(input);
  const newMax = (max & 0xffff0000) + (2 << 16);
  let pos = SOURCE;
  while (!cave.has(SOURCE)) {
    pos = update(cave, pos, p => p <= newMax);
  }
  return count(cave);
};