#include 
     
      #include 
      
       #include 
       
        #include 
        
         using namespace std;struct TreeNode {    int val;    TreeNode *left;    TreeNode *right;    TreeNode(int x) : val(x), left(NULL), right(NULL) {}};class Solution {public:    vector
         
          
            > levelOrder(TreeNode *root) { result.clear(); if (!root) return result; queue
           
             q;//层序遍历需要一个queue q.push(root); queue
            
              tmpQ;//因为每一层要分开，所以另开辟一个queue缓存一层 while(!q.empty()){ while(!q.empty()){ tmpQ.push(q.front()); q.pop(); } vector
             
               oneLevel; while(!tmpQ.empty()){ oneLevel.push_back(tmpQ.front()->val);//对于该层全部遍历 if (tmpQ.front()->left) q.push(tmpQ.front()->left); if (tmpQ.front()->right) q.push(tmpQ.front()->right); tmpQ.pop(); } result.push_back(oneLevel); } return result; }private: vector
              
               
                 > result;//!!};int main(){ return 0;}
               
              
             
            
           
          
         
        
       
      
     

 

 

 

 

 

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