[LeetCode] Sum Root to Leaf Numbers dfs,深度搜索

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.

#include <iostream>
using namespace std;

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

class Solution {
public:
    int sumNumbers(TreeNode *root) {
        unsigned int cur_val=0,ret_val=0;
        help_f(root,cur_val,ret_val);
        return ret_val;
    }
    void help_f(TreeNode *node,unsigned int &cur_val,unsigned int &ret_val)
    {
        if(node==NULL)  return ;
        cur_val=cur_val*10+node->val;
        help_f(node->left,cur_val,ret_val);
        help_f(node->right,cur_val,ret_val);
        if(node->left==NULL&&node->right==NULL) ret_val+=cur_val;
        cur_val/=10;
    }
};

int main()
{

    return 0;
}