AOC 2022 - Day 3

index.js

const fs = require("fs/promises");
const mainInput = "input.txt";
const example = "example.txt";
const example2 = "example2.txt";

async function readInput(fileName) {
	const file = await fs.readFile(fileName, "utf-8");
	return file.trim().replace(/\r/g, "").split("\n");
}

const priorities = {
	a: 1,
	b: 2,
	c: 3,
	d: 4,
	e: 5,
	f: 6,
	g: 7,
	h: 8,
	i: 9,
	j: 10,
	k: 11,
	l: 12,
	m: 13,
	n: 14,
	o: 15,
	p: 16,
	q: 17,
	r: 18,
	s: 19,
	t: 20,
	u: 21,
	v: 22,
	w: 23,
	x: 24,
	y: 25,
	z: 26,

	A: 27,
	B: 28,
	C: 29,
	D: 30,
	E: 31,
	F: 32,
	G: 33,
	H: 34,
	I: 35,
	J: 36,
	K: 37,
	L: 38,
	M: 39,
	N: 40,
	O: 41,
	P: 42,
	Q: 43,
	R: 44,
	S: 45,
	T: 46,
	U: 47,
	V: 48,
	W: 49,
	X: 50,
	Y: 51,
	Z: 52,
};

async function solveFirst(fileName) {
	const inputs = await readInput(fileName);

	let prioSum = 0;
	inputs.forEach((ruck, idx) => {
		let compartments = [
			ruck.substring(0, ruck.length / 2),
			ruck.substring(ruck.length / 2),
		];
		//console.log(`====================\nRuck: ${idx}\nCompartments: ${compartments}\n====================`);
		let items1 = compartments[0].split("");
		let items2 = compartments[1].split("");
		let sharedItem = items1.filter((i1) => items2.some((i2) => i1 === i2));
		prioSum += priorities[sharedItem[0]];
	});
	return prioSum;
}

async function solveTwo(fileName) {
	const file = await readInput(fileName);
	const groups = [];
	let group = [];
	let prioSum = 0;

	for (const line of file) {
		group.push(line);
		if (group.length === 3) {
			groups.push(group);
			group = [];
		}
	}

	groups.forEach((group) => {
		let items1 = group[0].split("");
		let items2 = group[1].split("");
		let items3 = group[2].split("");

		let sharedItem = items1.filter(
			(i1) => items2.some((i2) => i1 === i2) && items3.some((i3) => i1 === i3)
		);
		prioSum += priorities[sharedItem[0]];
	});

	return prioSum;
}

(async () => {
	const partOne = await solveFirst(mainInput);
	const partTwo = await solveTwo(mainInput);
	console.log(partOne);
	console.log(partTwo);
})();