# LeetCode129：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.

#include <iostream>
#include <vector>

using namespace std;

/*
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) {}
* };
*/

struct TreeNode {
int val;
TreeNode *left;
TreeNode *right;
TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};

{
if(root == NULL)
{
TreeNode *node = new TreeNode(val);
root = node;
}
else if(root->val < val)
{
}
else if(root->val > val)
{
}
}

void printTree(TreeNode *root)
{
if(root)
{
cout<<root->val<<" ";
printTree(root->left);
printTree(root->right);
}
}
class Solution {
public:
int sumNumbers(TreeNode *root) {
if(root == NULL)
return 0;
int sum = 0;
vector<int> v;
dfs(root, v, sum);
return sum;
}

void dfs(TreeNode *node, vector<int> &v, int &sum)
{
if(node == NULL)
return ;

v.push_back(node->val);
if(node->left == NULL && node->right == NULL)
{
vector<int>::iterator iter;
int tmp = 0;
for(iter = v.begin(); iter != v.end(); ++iter)
tmp =tmp*10 + *iter;
sum += tmp;

}
else
{
if(node->left)
dfs(node->left, v, sum);
if(node->right)
dfs(node->right, v, sum);
}
v.pop_back();

}
};
int main(void)
{
TreeNode *root = new TreeNode(5);
}