[LEETCODE] Sum Root to Leaf Numbers

LINK:http://leetcode.com/onlinejudge#question_129

大意：题目给出一颗二叉树，要求你求出从根到叶子的一条路径上所有数字构成数的和

    1
   / \
  2   3

12 + 13 = 25

/**
* Definition for binary tree
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/

二叉树遍历 简单递归题？

class Solution {
public:
    int tot;
    void gao(TreeNode *p, int sum){
        if(p ==NULL)
            return;
        if(p->left == NULL && p->right ==NULL){
            tot += sum*10 + p->val;
        }
        if(p->left!=NULL){
            gao(p->left, sum*10+p->val);
        }
        if(p->right!=NULL){
            gao(p->right, sum*10+p->val);
        }
    }
    int sumNumbers(TreeNode *root) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        tot = 0;
        gao(root,0);
        return tot;
    }
};