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.
给定一棵二叉树，节点值只可能是[0-9]区间上的值，每一条从根到叶子的节点都可以看成一个整数，现要求把所有路径表示的整数相加，返回和
/**
* Definition for binary tree
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
void dfs(int&result, int num, TreeNode*node){
//result表示所有路径的组合
//num表示根到node的父节点的组合数
if(node){
num=10*num+node->val; //计算从根到当前节点的组合数
if(node->left==NULL && node->right==NULL){
result+=num; //已经找到一个条路径的组合数，累加到result上
return;
}
if(node->left) dfs(result, num, node->left);
if(node->right) dfs(result, num, node->right);
}
}
int sumNumbers(TreeNode *root){
if(root==NULL)return NULL;
int result=0;
int num=0;
dfs(result, num, root);
return result;
}
};LeetCode: Sum Root to Leaf Numbers [129],布布扣,bubuko.com
LeetCode: Sum Root to Leaf Numbers [129]
原文地址：http://blog.csdn.net/harryhuang1990/article/details/34126865
