102.cpp

//
//  102.cpp
//  leetcode
//
//  Created by R Z on 2018/8/5.
//  Copyright © 2018年 R Z. All rights reserved.
//

#include <stdio.h>
#include <vector>
#include <queue>
using namespace std;
/**
 * Definition for a binary tree node.*/
struct TreeNode {
    int val;
    TreeNode *left;
    TreeNode *right;
    TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 };
class Solution {
public:
    vector<vector<int>> levelOrder(TreeNode* root) {
        vector<vector<int>> res;
        if(root==NULL) return res;
        queue<TreeNode*> q;
        q.push(root);
        while(!q.empty()){
            int n=q.size();
            vector<int> tmp;
            for(int i=0;i<n;i++){
                TreeNode* node=q.front();
                q.pop();
                tmp.push_back(node->val);
                if(node->left) q.push(node->left);
                if(node->right) q.push(node->right);
            }
            res.push_back(tmp);
        }
        return res;
    }
};