LeetCode 429 N叉树的层次遍历[BFS] HERODING的LeetCode之路

解题思路：
非常常规的一道N叉树层次遍历问题，略微修改一下二叉树层次遍历的BFS模板就可以轻松解决，代码如下：

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

    Node() {}

    Node(int _val) {
        val = _val;
    }

    Node(int _val, vector _children) {
        val = _val;
        children = _children;
    }
};
*/

class Solution {
public:
    vector<vector<int>> levelOrder(Node* root) {
        vector<vector<int>> res;
        if(root == nullptr) return res;
        queue<Node*> q;
        q.push(root);
        while(!q.empty()) {
            int n = q.size();
            vector<int> temp;
            for(int i = 0; i < n; i ++) {
                Node* node = q.front();
                q.pop();
                temp.push_back(node->val);
                for(auto& child : node->children) {
                    q.push(child);
                }
            }
            res.push_back(move(temp));
        }
        return res;
    }
};```