Leetcode 226 Invert Binary Tree

 1 /**
 2  * Definition for a binary tree node.
 3  * struct TreeNode {
 4  *     int val;
 5  *     TreeNode *left;
 6  *     TreeNode *right;
 7  *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 8  * };
 9  */
10 class Solution {
11 public:
12     void swapLR(TreeNode* root){
13         if(!root) return;
14         else{
15             TreeNode *t = root->left;
16             root->left = root->right;
17             root->right = t;
18             swapLR(root->left);
19             swapLR(root->right);
20         }
21     
22     }
23     TreeNode* invertTree(TreeNode* root) {
24         swapLR(root);
25         return root;
26     }
27 };