const fs = require('fs'); const input = fs.readFileSync(__dirname + '/input.txt', 'utf8').split("\n"); interface Coord { x: number, y: number, }; enum Dir { Up, Right, Down, Left, }; const map: Array> = []; const width = 71; const height = 71; for (let y = 0; y < height; y++) { if (!map[y]) { map[y] = []; } for (let x = 0; x < width; x++) { map[y][x] = '.'; } } for (let i = 0; i < 1024; i++) { const [x, y] = input[i].split(',').map((st: string) => parseInt(st)); map[y][x] = '#' } function get(pos: Coord): string|number { if (map[pos.y] && map[pos.y][pos.x]) { return map[pos.y][pos.x]; } return '#'; } function set(pos: Coord, val: string|number): void { map[pos.y][pos.x] = val; } function nextDir(dir: Dir): Dir { const directions = [Dir.Up, Dir.Right, Dir.Down, Dir.Left]; const i = (directions.indexOf(dir) + 1) % directions.length; return directions[i]; } function prevDir(dir: Dir): Dir { const directions = [Dir.Up, Dir.Right, Dir.Down, Dir.Left]; const i = directions.indexOf(dir) - 1; if (i < 0) { return directions[directions.length - 1]; } return directions[i]; } function printMap(path: Array = []) { const mapClone = map.slice().map((row: Array) => row.slice()); path.forEach(({ x, y }) => { mapClone[y][x] = 'O'; }); console.log(mapClone.map((row: Array) => row.map((c) => typeof c === 'number' ? '.' : c).join('')).join("\n")); console.log("\n"); } function nextCoord(pos: Coord, direction: Dir): Coord { return direction === Dir.Up ? { x: pos.x, y: pos.y - 1 } : (direction === Dir.Right ? { x: pos.x + 1, y: pos.y } : (direction === Dir.Down ? { x: pos.x, y: pos.y + 1 } : { x: pos.x - 1, y: pos.y }) ); } function isDeadEnd(pos: Coord): boolean { if ((pos.x === 0 && pos.y === 0) || (pos.x === width - 1 && pos.y === width - 1)) { return false; } const adjs = [Dir.Up, Dir.Right, Dir.Down, Dir.Left].map((dir) => get(nextCoord(pos, dir))).join(''); return adjs === '###.' || adjs === '##.#' || adjs === '#.##' || adjs === '.###'; } function fillDeadEnd(pos: Coord): void { set(pos, '#') for (let dir of [Dir.Up, Dir.Right, Dir.Down, Dir.Left]) { const next = nextCoord(pos, dir); if (get(next) === '.') { if (isDeadEnd(next)) { fillDeadEnd(next); } } }; } printMap(); for (let y = 0; y < height; y++) { for (let x = 0; x < width; x++) { const pos = { x, y }; const char = get(pos); if (char !== '.') { continue; } if (isDeadEnd(pos)) { fillDeadEnd(pos); } } } printMap(); for (let i = 1025; i < input.length; i++) { const byte = input[i].split(',').map((c: string) => parseInt(c)); set({ x: byte[0], y: byte[1] }, '#'); for (let y = 0; y < height; y++) { for (let x = 0; x < width; x++) { const pos = { x, y }; let char = get(pos); if (typeof char === 'number') { set(pos, '.'); } } } let finished = false; function getScoresAfterPosition(pos: Coord, dir: Dir, path: Array = []): void { if (finished) { return; } [dir, nextDir(dir), prevDir(dir)].forEach((newDir, i) => { if (finished) { return; } const next = nextCoord(pos, newDir); if (next.x === width - 1 && next.y === height - 1) { finished = true; return; } const nextCell = get(next); if (nextCell !== '#' && (typeof nextCell !== 'number' || nextCell > path.length) && !path.find(({ x, y }) => next.x === x && next.y === y)) { set(next, path.length); getScoresAfterPosition(next, newDir, [...path, next]); } }); return; } getScoresAfterPosition({ x: 0, y: 0 }, Dir.Right, [{ x: 0, y: 0 }]); console.log(i, byte); printMap(); if (!finished) { console.log('blocked'); break; } }