Node.js) 백준 16929번: Two Dots

https://www.acmicpc.net/problem/16929

16929번: Two Dots

const fs = require("fs");
const input = fs.readFileSync("./dev/stdin").toString().trim().split("\n");

const [N, M] = input.shift().split(" ").map(Number);
const board = input.map((r) => r.split(""));

let visited = Array.from(Array(N), () => Array(M).fill(false));
const dx = [1, -1, 0, 0];
const dy = [0, 0, -1, 1];
let cycle = false;
let sx;
let sy;

const dfs = (x, y, px, py, cnt) => {
  if (cycle) return;

  for (let i = 0; i < 4; i++) {
    const nx = x + dx[i];
    const ny = y + dy[i];

    if (
      nx < 0 ||
      nx >= N ||
      ny < 0 ||
      ny >= M ||
      board[nx][ny] != board[x][y] ||
      (nx == px && ny == py)
    )
      continue;

    if (!visited[nx][ny]) {
      visited[nx][ny] = true;
      dfs(nx, ny, x, y, cnt + 1);
      visited[nx][ny] = false;
    } else if (cnt >= 4 && visited[nx][ny]) {
      cycle = true;
      return;
    }
  }
};

for (let i = 0; i < N; i++) {
  for (let j = 0; j < M; j++) {
    visited[i][j] = true;
    dfs(i, j, -1, -1, 1);
    visited[i][j] = false;
    if (cycle) break;
  }
  if (cycle) break;
}

console.log(cycle ? "Yes" : "No");