/*

 struct TreeNode {

     int val;

     struct TreeNode *left;

     struct TreeNode *right;

     TreeNode(int x) :

             val(x), left(NULL), right(NULL) {

     }

 };*/

 class Solution {

 public:

     vector<int> PrintFromTopToBottom(TreeNode *root) {

         vector<int> res;

         queue<TreeNode*> que;

         if(!root)

             return res;

         que.push(root);

         while(que.size()!=)

         {

             TreeNode *r=que.front();

             que.pop();

             res.push_back(r->val);

             if(r->left)

                 que.push(r->left);

             if(r->right)

                 que.push(r->right);

         }

         return res;

     }

 };