翻转一棵二叉树。
示例：
思想 递归
java版
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
class Solution {
public TreeNode invertTree(TreeNode root) {
if(root == null) {
return root;
}
TreeNode temp = invertTree(root.left);
root.left = invertTree(root.right);
root.right = temp;
return root;
}
}
运行结果
