二叉树中和为某一值的路径

package Leetcode;
import java.util.*;
//输入一棵二叉树和一个整数，打印出二叉树中节点值的和为输入整数的所有路径。从树的根节点开始往下一直到叶节点所经过的节点形成一条路径。
//回溯
public class test34 {
    public static void main(String[] args) {
        TreeNode root=new TreeNode(5);
        root.left=new TreeNode(4);
        root.right=new TreeNode(8);
        root.left.left=new TreeNode(11);
        root.right.left=new TreeNode(13);
        root.right.right=new TreeNode(4);
        root.left.left.left=new TreeNode(7);
        root.left.left.right=new TreeNode(2);
        root.right.right.left=new TreeNode(5);
        root.right.right.right=new TreeNode(1);
        int sum=22;
        List<List<Integer>> list=pathSum(root, sum);    
        int x=0;
    }
    public static List<List<Integer>> pathSum(TreeNode root, int sum) {
        if(root==null){
            return new ArrayList<>();
        }
        List<List<Integer>> result=new ArrayList();
        helper(root,sum,new ArrayList<>(),result);
        return result;
    }
    public static void helper(TreeNode root, int sum,List<Integer> temp,List<List<Integer>> list) {
        if(root==null){
            return;
        }
        temp.add(root.val);
        if(root.left==null&&root.right==null){
            if(sum==root.val){
                list.add(new ArrayList<>(temp));
                
            }
            temp.remove(temp.size()-1);
            return;
        }
        helper(root.left, sum-root.val, temp, list);
        helper(root.right, sum-root.val, temp, list);
        temp.remove(temp.size()-1);
      
        

        
    }

}