JS图递归与迭代DFS阶差

function dfsRecursive(graph, start, visited) {
  visited[start] = true;
  console.log(start);

  for (let neighbor of graph[start]) {
    if (!visited[neighbor]) {
      dfsRecursive(graph, neighbor, visited);
    }
  }
}

const graph = {
  A: ['B', 'C'],
  B: ['A', 'D', 'E'],
  C: ['A', 'F'],
  D: ['B'],
  E: ['B', 'F'],
  F: ['C', 'E']
};

const visited = {};
dfsRecursive(graph, 'A', visited);

function dfsIterative(graph, start) {
  const stack = [start];
  const visited = {};

  while (stack.length > 0) {
    const vertex = stack.pop();
    if (!visited[vertex]) {
      visited[vertex] = true;
      console.log(vertex);
      for (let neighbor of graph[vertex]) {
        stack.push(neighbor);
      }
    }
  }
}

const graph = {
  A: ['B', 'C'],
  B: ['A', 'D', 'E'],
  C: ['A', 'F'],
  D: ['B'],
  E: ['B', 'F'],
  F: ['C', 'E']
};

dfsIterative(graph, 'A');