Discussion on: Advent of code - Day 7

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Replies for: For once, the JS version is compact :) - where's part 2, though ? 😊 A flat structure is indeed simpler to manage, given that we have to traverse...

This is part 2!

Actually I always traversed in the same order. I just bruteforced in part 1, trying all possible start point 😂 This is my part 1 solution:

const tree = input.reduce((tree, line) => {
  const color = /(^.*) bags contain/.exec(line)[1];
  tree[color] = [];

  const matches = line.matchAll(/,? \d+ ([^,.]*) bags?/g);
  for (const match of matches) {
    tree[color].push(match[1]);
  }
  return tree;
}, {});

const canContainGold = (color) => {
  if (tree[color].includes("shiny gold")) return true;
  return tree[color].some((color) => canContainGold(color));
};

const filtered = Object.keys(tree).filter((color) => {
  return canContainGold(color);
});

console.log(filtered.length);

Olivier Guimbal • Dec 8 '20

oh yes right :)