# leetcode No113. Path Sum II

2016-08-26 09:35:33         来源：wc19930807的博客

# Question：

Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum.

For example:
Given the below binary tree andsum = 22,
```              5
/ \
4   8
/   / \
11  13  4
/  \    / \
7    2  5   1
```

return

```[
[5,4,11,2],
[5,8,4,5]
]
```

DFS

# Accepted Code：

```/**
* 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:
vector> pathSum(TreeNode* root, int sum) {
vector> res;
vector temp;
help(root,res,temp,sum);
return res;
}
void help(TreeNode* root,vector> &res,vector v,int sum)
{
if(root==NULL)
return;
v.push_back(root->val);
if(root->left==NULL&&root->right==NULL&&root->val==sum)
{
res.push_back(v);
return;
}
else if(root->left==NULL&&root->right==NULL)
return;
else
{
if(root->left)
help(root->left,res,v,sum-root->val);
if(root->right)
help(root->right,res,v,sum-root->val);
}
}
};```