Advent of Code 22 — 13b

13b.js

const fs = require('fs');
const readline = require('readline');

function compare(left, right) {
    for (let i = 0; i < Math.max(left.length, right.length); i++) {
        let leftValue = left.at(i);
        let rightValue = right.at(i);

        if (leftValue === undefined) return -1;
        if (rightValue === undefined) return 1;

        if (Number.isInteger(leftValue) && Number.isInteger(rightValue)) {
            if (leftValue !== rightValue) {
                return leftValue - rightValue;
            }
        } else {
            if (Number.isInteger(leftValue)) leftValue = [leftValue];
            if (Number.isInteger(rightValue)) rightValue = [rightValue];

            return compare(leftValue, rightValue);
        }
    }
}

async function processLineByLine(file) {
    const fileStream = fs.createReadStream(file);

    const rl = readline.createInterface({
        input: fileStream,
        crlfDelay: Infinity
    });

    let iteration = 0;
    const cases = [];
    for await (const line of rl) {
        if ([0, 1].includes(iteration % 3)) {
            cases.push(JSON.parse(line));
        }
        iteration++;
    }

    const first_injection = [[2]];
    const second_injection = [[6]];
    cases.push(first_injection, second_injection);
    
    cases.sort(compare);

    const idx_first_inj = cases.indexOf(first_injection) + 1;
    const idx_second_inj = cases.indexOf(second_injection) + 1;

    console.log(`${file}: ${idx_first_inj * idx_second_inj}`);
}

processLineByLine('13.test.txt');
processLineByLine('13.main.txt');