## 【leetcode】113. Path Sum II

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

Note: A leaf is a node with no children.

Example:

Given the below binary tree and `sum = 22`,

```      5
/ \
4   8
/   / \
11  13  4
/  \    / \
7    2  5   1
```

Return:

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

``````/**
* Definition for a binary tree node.
* public class TreeNode {
*     int val;
*     TreeNode left;
*     TreeNode right;
*     TreeNode(int x) { val = x; }
* }
*/
class Solution {
public List<List<Integer>> pathSum(TreeNode root, int sum) {
List<List<Integer>> result = new ArrayList<>();
if(root == null){
return result;
}
List<Integer> list = new ArrayList<>();
dfs(root,sum,list,result);
return result;
}

public void dfs(TreeNode root,int sum,List<Integer> list,List<List<Integer>> result){
sum -= root.val;
if(root.left==null && root.right==null){
if(sum==0){
return ;
}
}
if(root.left != null){
dfs(root.left,sum,list,result);
//复位
list.remove(list.size()-1);
}
if(root.right != null){
dfs(root.right,sum,list,result);
list.remove(list.size()-1);
}

}
}``````