(leetcode )Sum Root to Leaf Numbers

Given a binary tree containing digits from

0-9

only, each root-to-leaf path could represent a number.An example is the root-to-leaf path

1->2->3

which represents the number

123

.Find the total sum of all root-to-leaf numbers.For example,

    1   / \  2   3

The root-to-leaf path

1->2

represents the number

12

.The root-to-leaf path

1->3

represents the number

13

.Return the sum = 12 + 13 =

25

 * Definition for binary tree * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */class Solution {    void test(TreeNode *root, int parent, int &s){        if(root->left==NULL&&root->right==NULL)        {            s+=parent*10+root->val;            return;        }        if(root->left!=NULL)            test(root->left, parent*10+root->val,s);        if(root->right!=NULL)            test(root->right, parent*10+root->val, s);    }public:    int sumNumbers(TreeNode *root) {        int parent = 0;        int s = 0;        if(root==NULL) return s;        test(root,parent,s);        return s;    }};