day07.js

const fs = require('fs').promises;

(async () => {
  console.log(`Reading input from ${__dirname}/${process.argv[2]}.txt`);
  const inputData = await fs.readFile(`${__dirname}/${process.argv[2]}.txt`);
  const inputs = inputData
    .toString()
    .split('\n')
    .filter((n) => n);

  const bagHolder = /^(?<color>\w+ \w+) bags? contain/;
  const subBag = / (?<num>\d+) (?<color>\w+ \w+) bags?(?:,|.)/g;

  const myBag = 'shiny gold';

  const bagMap = {};

  inputs.forEach((line) => {
    const outerBag = bagHolder.exec(line).groups.color;
    const subBags = [];

    let subBagExec = subBag.exec(line);
    while (subBagExec) {
      subBags.push({
        num: parseInt(subBagExec.groups.num, 10),
        color: subBagExec.groups.color,
      });
      subBagExec = subBag.exec(line);
    }

    bagMap[outerBag] = subBags;
  });

  const bagCounter = new Set();

  const goDown = (parentColor, bag) => {
    if (bag === myBag && parentColor !== myBag) {
      bagCounter.add(parentColor);
    }
    if (bagMap[bag].length === 0) {
      return;
    }
    bagMap[bag].forEach((subBag) => {
      return goDown(parentColor, subBag.color);
    });
  };

  Object.keys(bagMap).forEach((outerBag) => {
    goDown(outerBag, outerBag);
  });

  const countDownBags = (bag) => {
    if (bagMap[bag].length === 0) {
      return 0;
    }
    const sum = bagMap[bag].reduce((sum, bag) => {
      return sum + bag.num * countDownBags(bag.color) + bag.num;
    }, 0);

    return sum;
  };

  console.log('outerBagCount', bagCounter.size);
  console.log('bagCount', countDownBags(myBag));
})();