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。

1 /* 2 struct TreeNode { 3     int val; 4     struct TreeNode *left; 5     struct TreeNode *right; 6     TreeNode(int x) : 7             val(x), left(NULL), right(NULL) { 8     } 9 };10 */11 class Solution {12 public:13     vector
      
       
         > Print(TreeNode* pRoot) {14         vector
        
         
           > vec;15         if(pRoot == NULL) return vec;16 17         queue
          
            q;18         q.push(pRoot);19 20         while(!q.empty())21         {22             int lo = 0, hi = q.size();23             vector
           
             c;24 while(lo++ < hi)25 {26 TreeNode *t = q.front();27 q.pop();28 c.push_back(t->val);29 if(t->left) q.push(t->left);30 if(t->right) q.push(t->right);31 }32 vec.push_back(c);33 }34 return vec;35 }36 };