👨‍🏫 题目地址

😋 AC code

/*** Definition for a binary tree node.* public class TreeNode {*     int val;*     TreeNode left;*     TreeNode right;*     TreeNode() {}*     TreeNode(int val) { this.val = val; }*     TreeNode(int val, TreeNode left, TreeNode right) {*         this.val = val;*         this.left = left;*         this.right = right;*     }* }*/
class Solution {public TreeNode invertTree(TreeNode root){if(root == null)return root;TreeNode t = root.left;root.left = root.right;root.right = t;if (root.left != null)invertTree(root.left);if (root.right != null)invertTree(root.right);return root;}
}