import * as fs from "node:fs/promises";

export async function readFile(filename: string): Promise<number[][]> {
    const lines = await fs
        .readFile(filename, { encoding: "utf8" })
        .then((lines: string) => lines.split(/\n/))
        .then((lines: string[]) =>
            lines.filter((x) => x).map((x) =>
                x.split(/ +/).map((x) => Number(x))
            )
        );

    const l1: number[] = [];
    const l2: number[] = [];

    lines.forEach(([a, b]) => {
        l1.push(a);
        l2.push(b);
    });

    return [l1, l2];
}

export function solve(...lists: number[][]) {
    lists.forEach((l) => l.sort());

    let sum = 0;

    for (const i in lists[0]) {
        sum += Math.abs(lists[0][i] - lists[1][i]);
    }

    return sum;
}