[백준] 바이러스(9251)

// 백준에서는 첫번째 조건으로 input 받게 설정
// 내 맥북, desktop 에선 두번째걸로 선택됨
const input =
  process.platform === "linux"
    ? require("fs").readFileSync("/dev/stdin").toString().split("\n")
    : require("fs").readFileSync("./input.txt").toString().split("\n");

const computer = parseInt(input[0]);
const nodeCount = parseInt(input[1]);
const graph = [...Array(computer + 1)].map((el) => []);

for (let i = 2; i < 2 + nodeCount; i++) {
  const [from, to] = input[i].split(" ").map((num) => parseInt(num));
  graph[from].push(to);
  graph[to].push(from);
}


const visited = [];

const bfs = () => {
  const willVisit = [1];
  let answer = 0;

  while (willVisit.length > 0) {
    const data = willVisit.shift();
    if (!visited[data]) {
      visited[data] = true;
      willVisit.push(...graph[data]);
      answer++;
    }
  }

  console.log(answer - 1);
};

bfs();