AoC/2024/01/index.ts

const fs = require('fs');

const input = fs.readFileSync(__dirname + '/input.txt', 'utf8');

const arr1: Array<number> = [];
const arr2: Array<number> = [];

input.split("\n").forEach((n: string) => {
    if (n.match('^\s*$')) {
        return;
    }
    const ns = n.split('   ');
    arr1.push(parseInt(ns[0]));
    arr2.push(parseInt(ns[1]));
});

// Part 1
arr1.sort();
arr2.sort();

let sum = 0;

arr1.forEach((v, k) => {
    sum += Math.max(v, arr2[k]) - Math.min(v, arr2[k]);
});

console.log(sum);

// Part 2
const map: { [key: number]: number } = {};

arr2.forEach((v) => {
    if (typeof map[v] === 'undefined') {
        map[v] = 1;
    } else {
        map[v]++;
    }
});

let score = 0;

arr1.forEach((v) => {
    score += (v * (map[v] || 0));
});

console.log(score);