【leetcode】Binary Tree Right Side View

 1 class Solution {
 2 public:
 3     vector<int> rightSideView(TreeNode* root) {
 4         vector<int> ret;
 5         if(root==NULL) return ret;
 6 
 7         queue<TreeNode*> Q;
 8         Q.push(root);
 9         TreeNode * node;
10         while(!Q.empty()){
11             int qlen=Q.size();
12             for(int i=0;i<qlen;i++){
13                 node=Q.front();
14                 Q.pop();
15 
16                 if(node->left) Q.push(node->left);
17                 if(node->right) Q.push(node->right);
18 
19             }
20             ret.push_back(node->val);
21         }
22 
23         return ret;
24     }
25 };