part1.ts

import * as fs from 'fs';

const input = fs.readFileSync('input', 'utf8').split('\n');

let max = { x: 0, y: 0 };
const rocks = input.map((line) =>
	line.split(' -> ').map((pos) => {
		const [x, y] = pos.split(',').map((n) => Number(n));
		if (x > max.x) max.x = x;
		if (y > max.y) max.y = y;
		return { x, y };
	}),
);

const cave = new Array(max.y * 2).fill(0).map(() => new Array(max.x * 2).fill('.'));
for (const rock of rocks) {
	for (let i = 0; i < rock.length - 1; i++) {
		if (rock[i].x === rock[i + 1].x) {
			const from = Math.min(rock[i].y, rock[i + 1].y);
			const to = Math.max(rock[i].y, rock[i + 1].y);
			for (let y = from; y <= to; y++) {
				cave[y][rock[i].x] = '#';
			}
		} else {
			const from = Math.min(rock[i].x, rock[i + 1].x);
			const to = Math.max(rock[i].x, rock[i + 1].x);
			for (let x = from; x <= to; x++) {
				cave[rock[i].y][x] = '#';
			}
		}
	}
}

let count = 0;
let resting = true;

while (cave[0][500] === '.' && resting) {
	let sand = { x: 500, y: 0 };
	resting = false;
	while (cave[sand.y + 1] && !resting) {
		if (cave[sand.y + 1][sand.x] === '.') {
			sand.y++;
		} else if (cave[sand.y + 1][sand.x - 1] === '.') {
			sand.y++;
			sand.x--;
		} else if (cave[sand.y + 1][sand.x + 1] === '.') {
			sand.y++;
			sand.x++;
		} else {
			cave[sand.y][sand.x] = 'o';
			resting = true;
			count++;
		}
	}
}

console.log(count);