64 lines
1.2 KiB
JavaScript
64 lines
1.2 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) {
|
||
|
|
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 amount of trees on the slope.
|
||
|
|
*/
|
||
|
|
async function main(data) {
|
||
|
|
const grid = new Grid(data.split("\n").map((line) => line.trim()));
|
||
|
|
|
||
|
|
let x = 0;
|
||
|
|
let y = 0;
|
||
|
|
let trees = 0;
|
||
|
|
|
||
|
|
const dX = 3;
|
||
|
|
const dY = 1;
|
||
|
|
|
||
|
|
while (y < grid.lines.length) {
|
||
|
|
if (grid.get(x, y) === TREE) {
|
||
|
|
trees++;
|
||
|
|
}
|
||
|
|
|
||
|
|
x += dX;
|
||
|
|
y += dY;
|
||
|
|
}
|
||
|
|
|
||
|
|
return trees;
|
||
|
|
}
|
||
|
|
|
||
|
|
fs.readFile("input", (err, data) => {
|
||
|
|
if (err) throw err;
|
||
|
|
main(data.toString()).then(console.log).catch(console.error);
|
||
|
|
});
|