找出二叉树所有到叶子节点的路径

import java.util.*;

class TreeNode {
int val;
TreeNode left;
TreeNode right;

TreeNode(int x) {
val = x;
}
}

public class Solution {
public List<String> binaryTreePaths(TreeNode root) {
List<String> list = new ArrayList<>();
if (root == null)
return list;

if (root.left == null && root.right == null)
list.add(root.val + "");

for (String path : binaryTreePaths(root.left))
list.add(root.val + "->" + path);

for (String path : binaryTreePaths(root.right))
list.add(root.val + "->" + path);
return list;
}

public static void main(String[] args) {
TreeNode one = new TreeNode(1);
TreeNode two = new TreeNode(2);
TreeNode three = new TreeNode(3);
TreeNode five = new TreeNode(5);
one.left = two;
one.right = three;
two.right = five;

new Solution().binaryTreePaths(one).forEach(System.out::println);
}
}