·leetcode 226题 翻转二叉树
·题目描述
给你一棵二叉树的根节点 root ，翻转这棵二叉树，并返回其根节点。
示例 1：
输入：root = [4,2,7,1,3,6,9] 输出：[4,7,2,9,6,3,1]
示例 2：
输入：root = [2,1,3] 输出：[2,3,1]
示例 3：
输入：root = [] 输出：[]
·java代码
class Solution {public TreeNode invertTree(TreeNode root) {if(root == null) return null;TreeNode left = root.left;TreeNode right = root.right;root.left = right;root.right = left;invertTree(root.left);invertTree(root.right);return root;}public class TreeNode {int val;TreeNode left;TreeNode right;TreeNode(int x) { val = x;}TreeNode(int val, TreeNode left, TreeNode right) {this.val = val;this.left = left;this.right = right;}}
}
