LeetCode刷题笔记-递归-反转二叉树

 1 /**
 2  * Definition for a binary tree node.
 3  * public class TreeNode {
 4  *     int val;
 5  *     TreeNode left;
 6  *     TreeNode right;
 7  *     TreeNode(int x) { val = x; }
 8  * }
 9  */
10 class Solution {
11     public TreeNode invertTree(TreeNode root) {
12         if(root==null){
13             return null;
14         }
15         TreeNode temp= root.left;
16         root.left=root.right;
17         root.right=temp;
18         invertTree(root.left);
19         invertTree(root.right);
20         return root;
21     }
22 }