AdventOfCode/JS/day3/solution_b.js
Tobias Berger 731ab021fd
JavaScript Day 3
Signed-off-by: Tobias Berger <tobi.berger13@gmail.com>
2022-12-01 13:26:30 +01:00

73 lines
1.5 KiB
JavaScript

import fs from "fs";
const TREE = "#";
const FREE = ".";
class Grid {
/**
* Construct a new Grid from an array of lines
*
* @param {string[]} lines The lines of the repeating Grid.
*/
constructor(lines) {
this.lines = lines;
}
/**
* Get the field at the respective coordinate in the grid.
*
* @param {number} x X-Coordinate of the field to get.
* @param {number} y Y-Coordinate of the field to get.
*
* @returns {string} The field at the coordinate.
*/
get(x, y) {
if (y > this.lines.length)
throw new Error(`Out of range [${[x, y]}] max y ${this.lines.length}`);
const line = this.lines[y];
return line[x % line.length];
}
}
/**
* Main function for Puzzle A
*
* @param {string} data - Puzzle input as a single string.
* @returns {number} The number of trees on all slopes, multiplied.
*/
async function main(data) {
const grid = new Grid(data.split("\n").map((line) => line.trim()));
const slopes = [
[1, 1],
[3, 1],
[5, 1],
[7, 1],
[1, 2],
];
let result = 1;
for (const slope of slopes) {
const [dX, dY] = slope;
let x = 0;
let y = 0;
let trees = 0;
while (y < grid.lines.length) {
if (grid.get(x, y) === TREE) {
trees++;
}
x += dX;
y += dY;
}
result *= trees;
}
return result;
}
fs.readFile("input", (err, data) => {
if (err) throw err;
main(data.toString()).then(console.log).catch(console.error);
});