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.

For 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]
]

public class Solution {
public List<List<Integer>> pathSum(TreeNode root, int sum) {
List<List<Integer>> res=new ArrayList<List<Integer>>();
if(root==null) return res;
List<Integer> temp=new ArrayList<Integer>();
pathSum2(res,temp,sum,root,0);
return res;

}
public void pathSum2(List<List<Integer>> res,List<Integer> temp,int sum,TreeNode root,int k)
{

if(root.left==null && root.right==null)
{    temp.add(root.val);
if(k+root.val==sum)
{
List<Integer> new_temp=new ArrayList<Integer>(temp);
res.add(new_temp);

}
temp.remove(temp.size()-1);
return ;
}
temp.add(root.val);
if(root.left!=null)
{
pathSum2(res,temp,sum,root.left,k+root.val);

}
if(root.right!=null)
{
pathSum2(res,temp,sum,root.right,k+root.val);

}
temp.remove(temp.size()-1);
}
}