AoC 2024 day 11

// Advent of Code 2024 - Day 11
const fs = require("fs")

const input = fs.readFileSync(__dirname + (process.argv.includes("--test") ? "/test.txt" : "/input.txt"), "utf8")
const data = input.split(" ").map(Number)

function evolveStones(initialStones, blinks) {
    let stoneMap = new Map()
    const cache = new Map()

    for (const stone of initialStones) {
        stoneMap.set(stone, (stoneMap.get(stone) || 0) + 1)
    }

    for (let blink = 0; blink < blinks; blink++) {
        const newStoneMap = new Map()

        for (const [stone, count] of stoneMap.entries()) {
            let transformed

            if (cache.has(stone)) {
                transformed = cache.get(stone)
            } else {
                if (stone === 0) {
                    transformed = [1]
                } else if (stone.toString().length % 2 === 0) {
                    let str = stone.toString()
                    const mid = str.length / 2
                    const left = +str.slice(0, mid)
                    const right = +str.slice(mid)
                    transformed = [left, right]
                } else transformed = [stone * 2024]

                cache.set(stone, transformed)
            }

            for (const newStone of transformed) {
                newStoneMap.set(newStone, (newStoneMap.get(newStone) || 0) + count)
            }
        }

        stoneMap = new Map(newStoneMap)
    }

    return Array.from(stoneMap.values()).reduce((sum, count) => sum + count, 0)
}

console.time("Part 1 Time")
console.log("Part 1:", evolveStones(data, 25))
console.timeEnd("Part 1 Time")

console.time("Part 2 Time")
console.log("Part 2:", evolveStones(data, 75))
console.timeEnd("Part 2 Time")