Advent of Code 2023 - Day 20 - Part 2

const solvePart2 = (input) => {
  const data = parse(input);
  const modules = data.modules;
  const inputCycles = {};
  for (const input of data.rxInputs) {
    inputCycles[input] = {};
    for (const module of Object.values(modules)) {
      if (module.destinations.includes(input)) {
        inputCycles[input][module.label] = 1; // fix the off-by-one
      }
    }
  }
  const numberOfCyclesToDetermine = Object.values(inputCycles).reduce((sum, e) => sum + Object.keys(e).length, 0);
  let determinedCyclesCounter = 0;
  for (let cycle = 0; determinedCyclesCounter < numberOfCyclesToDetermine; cycle++) {
    const pulses = [
      {
        from: "button",
        to: "broadcaster",
        value: LOW_PULSE,
      },
    ];
    while (pulses.length > 0) {
      const pulse = pulses.shift(); // FIFO

      for (const input of data.rxInputs) {
        if (pulse.to == input && inputCycles[input][pulse.from] && pulse.value == HIGH_PULSE) {
          if (inputCycles[input][pulse.from] == 1) {
            inputCycles[input][pulse.from] += cycle;
            determinedCyclesCounter++;
            if (determinedCyclesCounter == numberOfCyclesToDetermine) {
              break;
            }
          }
        }
      }

      const module = modules[pulse.to];
      if (!module) {
        continue;
      }
      const newPulse = modulate(module, pulse);
      if (!newPulse) {
        continue;
      }
      for (const destination of module.destinations) {
        pulses.push({
          from: module.label,
          to: destination,
          value: newPulse,
        });
      }
    }
  }
  return Math.min(...Object.values(inputCycles).map((e) => Object.values(e).reduce((product, e) => product * e, 1)));
};