AoC/2024/11/index.ts

const fs = require('fs');

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

let stones: Array<string> = input.slice(0, -1).split(' ');

const countMap: { [key: string]: Array<number> } = {};

let sum = 0;

function getCountAfter(stone: string, blink: number) {
    const newStones: Array<string> = [];
    stones.forEach((stone) => {
        if (stone === '0') {
            newStones.push('1');
            return;
        }
        const len = stone.length;
        if (len % 2 === 0) {
            newStones.push(stone.slice(0, len / 2));
            let last = stone.slice(len / 2);
            newStones.push(''+(parseInt(last)));
            return;
        }
        newStones.push(''+(parseInt(stone) * 2024));
    });
    if (blink === 1) {
        return newStones;
    }
    return newStones.sum((newStone) => getCountAfter(newStone, blink - 1));
}

const blinks = 25;

stones.forEach((stone) => {
    sum += getCountAfter(stone, 25);
});

console.log(sum);