129_sumRoottoLeafNumbers

/*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   3The 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 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) {        int sum=0;        sumNodes(root,0,sum);        return sum;    }    void sumNodes(TreeNode* root,int tmp,int &sum){        if(!root) return;        tmp=tmp*10+root->val;        if(!root->left && !root->right){            sum+=tmp;        }         sumNodes(root->left,tmp,sum);        sumNodes(root->right,tmp,sum);    }};