Day 1: Historian Hysteria

Megathread guidelines

  • Keep top level comments as only solutions, if you want to say something other than a solution put it in a new post. (replies to comments can be whatever)
  • You can send code in code blocks by using three backticks, the code, and then three backticks or use something such as https://blocks.programming.dev if you prefer sending it through a URL

FAQ

  • @sjmulder
    1•23 hours ago

    JavaScript

    After writing a procedural to-the-point version in C, tried a JavaScript solution too because it’s just perfect for list comprehension. The part 2 search is inefficient but the data size is small.

    Code 
    const fs = require("fs");
const U = require("./util");

const pairs = fs
    .readFileSync(process.argv[2] || process.stdin.fd, "utf8")
    .split("\n")
    .filter(x => x != "")
    .map(x => x.split(/ +/).map(Number));

const ls = pairs.map(x => x[0]); ls.sort();
const rs = pairs.map(x => x[1]); rs.sort();

const p1 = U.sum(ls.map((l, i) => Math.abs(l - rs[i])));
const p2 = U.sum(ls.map(l => l * U.count(rs, l)));

console.log("01:", p1, p2);

    https://github.com/sjmulder/aoc/blob/master/2024/js/day01.js