输出二叉树所有路径，java

package main.java;/*
 * @Description: 遍历所有的树
 * @Author: du_zj
 * @Date: 2022/3/22.
 */

import java.util.ArrayList;
import java.util.List;

public class ListTree {


    public boolean hasPathSum(TreeNode root, int sum) {
        List<Integer> list = new ArrayList<>();
        dfs(root, list);
        List<String> strings = new ArrayList<>();
        helper(root, root.val + "", strings);
        System.out.println(strings);
        return true;
    }

    public void helper(TreeNode root, String path, List<String> result) {
        if (root == null) {
            return;
        }

        if (root.left == null && root.right == null) {
            result.add(path);
            return;
        }

        if (root.left != null) {
            helper(root.left, path + "->" + root.left.val, result);
        }

        if (root.right != null) {
            helper(root.right, path + "->" + root.right.val, result);
        }
    }



    List<List<Integer>> results = new ArrayList<>();
    public boolean hasPathSum2(TreeNode root, int sum) {
        List<Integer> list = new ArrayList<>();
        dfs(root, list);
        System.out.println(results.toString());
        return true;
    }



    private void dfs(TreeNode root, List<Integer> list) {
        if (root == null) {
            return;
        }
        if (root.left == null && root.right == null) {
            results.add(list);
        }
        list.add(root.val);
        if (root.left != null) {
            dfs(root.left, new ArrayList<>(list));
        }
        if (root.right != null) {
            dfs(root.right, new ArrayList<>(list));
        }
    }

    static class TreeNode{
        TreeNode left;
        TreeNode right;
        Integer val;

    }
    public static void main(String[] args) {
        TreeNode root1 = new TreeNode();
        TreeNode root2 = new TreeNode();
        TreeNode root3 = new TreeNode();
        TreeNode root4 = new TreeNode();
        TreeNode root5 = new TreeNode();
        root1.val = 10;
        root2.left = root1;
        root3.val = 8;
        root2.right = root3;
        root2.val = 6;
        root4.left = root2;
        root4.val = 2;
        root5.val = 0;
        root4.right = root5;
        int sum = 0;
        ListTree nv = new ListTree();
        nv.hasPathSum(root4,sum);
    }
}