> For the complete documentation index, see [llms.txt](https://dfine.gitbook.io/leetcode/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://dfine.gitbook.io/leetcode/429.n_ary_tree_level_order_traversal.md).

# 429.N Ary Tree Level Order Traversal

**429.N ary Tree Lever Order Traversal**

难度:Easy

> 给定一个 N 叉树，返回其节点值的层序遍历。 (即从左到右，逐层遍历)。

例如，给定一个 3叉树 :

![narytreeexample.png](https://i.loli.net/2019/03/30/5c9ee0080a1d8.png)

返回其层序遍历:

```
[
     [1],
     [3,2,4],
     [5,6]
]
```

说明:

树的深度不会超过 1000。 树的节点总数不会超过 5000。

方法：采用了队列的先进后出，迭代遍历所有节点。

```
/*
// Definition for a Node.
class Node {
public:
    int val;
    vector<Node*> children;

    Node() {}

    Node(int _val, vector<Node*> _children) {
        val = _val;
        children = _children;
    }
};
*/
class Solution {
public:
    vector<vector<int>> levelOrder(Node* root) {
        deque<Node*> d;
        vector<vector<int>> res;
        if(!root)
            return res;

        d.push_back(root);
        while(!d.empty())
        {
            vector<int >tmp;
            for(auto i: d)
                tmp.push_back(i->val);
            int len=d.size();
            while(len--)
            {
                if(d[0]->children.empty())
                    d.pop_front();
                else
                {

                    for(auto i: d[0]->children)
                        d.push_back(i);
                    d.pop_front();
                }
            }
            res.push_back(tmp);

        }
        return res;

    }
};
```