/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    vector<int> rightSideView(TreeNode* root) {
        vector<int> result;
        queue<TreeNode*> my_que;
        if(root == nullptr) return result;
        TreeNode* cur = root;
        my_que.push(cur);
        while(my_que.empty() != 1)
        {
           int size = my_que.size();
           for (int i=0 ; i<size ; i++)
           {
               cur = my_que.front();
               my_que.pop();
               //此时为该层次的最右点
               if(i == size-1) result.push_back(cur->val);
               if(cur->left != nullptr) my_que.push(cur->left);
               if(cur->right != nullptr) my_que.push(cur->right);
           }
        }
        return result;
    }
};