AdventOfCode/JS/day11/solution_a.mjs
Tobias Berger a043557d2d
JavaScript Day 11
Signed-off-by: Tobias Berger <tobi.berger13@gmail.com>
2022-12-01 13:26:33 +01:00

94 lines
2.4 KiB
JavaScript

import fs from "fs";
const EMPTY = "L";
const OCCUPIED = "#";
const FLOOR = ".";
class Field {
/**
* @param {string[][]} lines Lines of the field
*/
constructor(lines) {
this.lines = lines;
}
toString() {
return this.lines.map((line) => line.join("")).join("\n");
}
get occupiedSeatCount() {
return this.lines.reduce(
(result, line) => result + line.filter((val) => val === OCCUPIED).length,
0
);
}
/**
* Checks visible seats from a given position
*
* @param {number} x X-Coordinate of the seat to check
* @param {number} y Y-Coordinate of the seat to check
* @returns {Promise<number>} Amount of seats visible from the given position
*/
checkVisibleSeats(x, y) {
let occupiedNeighbors = 0;
for (let dY = -1; dY <= 1; dY++) {
const curLine = this.lines[y + dY];
if (curLine === undefined) continue;
for (let dX = -1; dX <= 1; dX++) {
if (dX === 0 && dY === 0) continue;
const curCell = curLine[x + dX];
if (curCell === OCCUPIED) occupiedNeighbors++;
}
}
return occupiedNeighbors;
}
/**
* @returns {number} Amount of seats that changed states.
*/
step() {
let changes = 0;
/** @type {string[][]} */
const changedLines = JSON.parse(JSON.stringify(this.lines));
for (let y = 0; y < this.lines.length; y++) {
for (let x = 0; x < this.lines[y].length; x++) {
const currentCell = this.lines[y][x];
if (currentCell === FLOOR) continue;
const occupiedNeighbors = this.checkVisibleSeats(x, y);
if (currentCell === EMPTY && occupiedNeighbors === 0) {
changedLines[y][x] = OCCUPIED;
changes++;
} else if (currentCell === OCCUPIED && occupiedNeighbors >= 4) {
changedLines[y][x] = EMPTY;
changes++;
}
}
}
this.lines = changedLines;
return changes;
}
}
/**
* Main function for Puzzle A
*
* @param {string} data - Puzzle input as a single string.
* @returns {number} Amount of open seats after applying all rules until stable.
*/
async function main(data) {
const lines = data.split(/\r?\n/).map((line) => line.split(""));
const field = new Field(lines);
let steps = 0;
while (field.step() > 0) {
// console.log("Step", ++steps);
}
return field.occupiedSeatCount;
}
fs.readFile("input", (err, data) => {
if (err) throw err;
main(data.toString()).then(console.log).catch(console.error);
});