그래프 순회 (BFS / DFS)

1function bfs(graph, start) {
2  const visited = new Set();
3  const queue = [start];
4  while (queue.length > 0) {
5    const node = queue.shift();
6    if (visited.has(node)) continue;
7    visited.add(node);
8    for (const neighbor of graph[node]) {
9      if (!visited.has(neighbor)) {
10        queue.push(neighbor);
11      }
12    }
13  }
14  return [...visited];
15}