199. Binary Tree Right Side View lnk

//https://leetcode.com/problems/binary-tree-right-side-view/
/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    vector<int> res;
    int mxdepth = 0;
 //   int cur = 1;
    void foo(TreeNode* root, int cur) {
        if(root){
            if(cur>mxdepth){
                res.push_back(root->val);
                mxdepth++;
            }
             foo(root->right,cur+1);
             foo(root->left,cur+1);
            
        }
    }
    
    
    vector<int> rightSideView(TreeNode* root) {
        foo(root,1);
       return res;
    }
};