Leetcode 226: Invert Binary Tree

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