/**

 * 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:

    int sumNumbers(TreeNode* root) {

        if(root == NULL) return ;

        int res = ;

        DFS(root,res,);

        return res;

    }

    void DFS(TreeNode* root,int &res,int add){

        if(root->left == NULL && root->right == NULL){

            add = add* + root->val;

            res += add;

            return;

        }

        add = add* + root->val;

        if(root->left != NULL){

            DFS(root->left,res,add);

        }

        if(root->right != NULL){

            DFS(root->right,res,add);

        }

    }

};