const fs = require('fs');

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

interface Coord { x: number, y: number };

const topo: Array<string> = input.split("\n").slice(0, -1);

const height = topo.length;
const width = topo[0].length;


let sum = 0;

function getScore({ x, y }: Coord, height = 0, trail: Array<Coord> = [], peaks: Array<string> = []): number {
    let score = 0;

    const nextHeight = height + 1;
    [
        { x, y: y - 1 },
        { x, y: y + 1 },
        { x: x - 1, y },
        { x: x + 1, y },
    ].forEach((coord) => {
        if (!topo[coord.y] || !topo[coord.y][coord.x]) {
            return;
        }
        if (parseInt(topo[coord.y][coord.x]) === nextHeight) {
            if (nextHeight === 9) {
                const coordString = `${coord.x},${coord.y}`;
                if (!peaks.includes(coordString)) {
                    score += 1;
                    // peaks.push(coordString); // Only for Part 1
                }
            } else {
                score += getScore(coord, nextHeight, [...trail, { x, y }], peaks);
            }
        }
    });

    return score;
}

let y = 0;
let x = 0;
for (let i = 0; i <= input.length; i++) {
    const char = input[i];
    if (char === "\n") {
        y++;
        x = 0;
        continue;
    }

    if (char === '0') {
        const score = getScore({ x, y });
        sum += score;
    }

    x++;
}

console.log(sum);