Prove safety offer: a binary tree and the paths to a certain value (recursively)

topic:

An input binary tree root node and an integer, the binary print values ​​of nodes in the input path and all integers. Forming a path to the path definition begins from the root node of the tree down to the leaf node has been traversed nodes. (Note: the return value in the list, a large array Array front)

answer:

Recursively, as follows:

import java.util.ArrayList;
/**
public class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;

    }

}
*/
public class Solution {
    public ArrayList<ArrayList<Integer>> FindPath(TreeNode root,int target) {
        ArrayList<ArrayList<Integer>> result = new ArrayList<>();
        ArrayList<Integer> list = new ArrayList<>();
        if(root==null){
            return result;
        }
        
        list.add(root.val);
        recursive(root,target,result,list);
        return result;
    }
    public void recursive(TreeNode root,int target,ArrayList<ArrayList<Integer>> result,ArrayList<Integer> list){
        if(root.val==target&&root.left==null&&root.right==null){
            result.add(list);
        }
        if(root.left!=null){
            ArrayList<Integer> leftList = new ArrayList<>();
            leftList.addAll(list);
            leftList.add(root.left.val);
            recursive(root.left,target-root.val,result,leftList);
        }
        if(root.right!=null){
            ArrayList<Integer> rightList = new ArrayList<>();
            rightList.addAll(list);
            rightList.add(root.right.val);
            recursive(root.right,target-root.val,result,rightList);
        }
    }
}