Advent of Code 2023-20a

function solve(input) {
  return process(parse(input));
}

function parse(input) {
  const mods = {};
  const inputs = {};
  input.split("\n").forEach((l) => {
    const {
      groups: { t, k, m },
    } = l.match(/(?<t>[%&]?)(?<k>.+) -> (?<m>.+)/);
    mods[k] = { t, to: m.split(", "), s: 0 };
    m.split(", ").forEach((m) => {
      inputs[m] ??= {};
      inputs[m][k] = 0;
    });
  });

  return [mods, inputs];
}

function process([mods, inputs]) {
  let sum = [0, 0];
  const queue = [];

  for (let i = 0; i < 1000; i++) {
    sum[0]++;
    queue.push(["button", "broadcaster", 0]);
    while (queue.length) {
      let [from, mod, pulse] = queue.shift();
      if (mod === "output") continue;
      if (mod === "rx") continue;
      const { t, to, s } = mods[mod];
      if (mod === "broadcaster") {
        for (const m of to) queue.push([mod, m, pulse]), sum[pulse]++;
        continue;
      }
      if (t === "%" && pulse === 0) {
        mods[mod].s = s ? 0 : 1;
        const nPulse = s ? 0 : 1;
        for (const m of mods[mod].to)
          queue.push([mod, m, nPulse]), sum[nPulse]++;
        continue;
      }
      if (t === "&") {
        inputs[mod][from] = pulse;
        const nPulse = Object.values(inputs[mod]).every(Boolean) ? 0 : 1;
        for (const m of to) queue.push([mod, m, nPulse]), sum[nPulse]++;
        continue;
      }
    }
  }

  return sum[0] * sum[1];
}