题目描述

从上到下按层打印二叉树，同一层结点从左至右输出。每一层输出一行。

/*
struct TreeNode {
    int val;
    struct TreeNode *left;
    struct TreeNode *right;
    TreeNode(int x) :
            val(x), left(NULL), right(NULL) {
    }
};
*/
class Solution {
public:
    vector<vector<int> > Print(TreeNode* pRoot) {
        vector<vector<int>> tVecVec;
        if(pRoot == NULL)
        {
            return tVecVec;
        }
        
        queue<TreeNode*> que;
        que.push(pRoot);
        while(que.size())
        {
            int length = que.size();
            vector<int> vec;
            for(int i = 0; i < length; ++i)
            {
                TreeNode* tmp = que.front();
                vec.push_back(tmp->val);
                que.pop();
                if(tmp->left) que.push(tmp->left);
                if(tmp->right) que.push(tmp->right);
            }
            
            tVecVec.push_back(vec);
            vec.clear();
        }
        
        return tVecVec;
    }
};