AdventOfCode/JS/day7/solution_b.mjs
Tobias Berger 065bca3e14
JavaScript Day 7
Signed-off-by: Tobias Berger <tobi.berger13@gmail.com>
2022-12-01 13:26:31 +01:00

58 lines
1.6 KiB
JavaScript

import fs from "fs";
const CONTENT_REGEX = /^(\d+) (\w+ \w+) bags?.?$/;
/**
* Main function for Puzzle B
*
* @param {string} data - Puzzle input as a single string.
* @returns {number} Amount of bags inside a shiny golden bag.
*/
async function main(data) {
const lines = data.split(/\r?\n/);
/** @type {Object.<string, [number, string][]>} */
const contentsOf = {};
/** @type {Object.<string, [number, string][]>} */
const containedBy = {};
for (const line of lines) {
const [bag, content] = line.split(" bags contain ");
contentsOf[bag] = [];
if (content === "no other bags.") continue;
contentsOf[bag] = content.split(", ").map((entry) => {
const [, count, containedBag] = entry.match(CONTENT_REGEX);
return [parseInt(count), containedBag];
});
for (const [count, containedBag] of contentsOf[bag]) {
if (!containedBy.hasOwnProperty(containedBag))
containedBy[containedBag] = [];
containedBy[containedBag].push([count, bag]);
}
}
/**
* @param {string} bag Bag to count contents of.
* @returns {number} Total amount of bags inside bag, recursively.
*/
function countBags(bag) {
if (!contentsOf.hasOwnProperty(bag)) {
return 0;
}
const contents = contentsOf[bag];
let result = contents.reduce((prev, cur) => prev + cur[0], 0);
result += contents.reduce(
(prev, cur) => prev + cur[0] * countBags(cur[1]),
0
);
return result;
}
return countBags("shiny gold");
}
fs.readFile("input", (err, data) => {
if (err) throw err;
main(data.toString()).then(console.log).catch(console.error);
});