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     TreeNode* invertTree(TreeNode* root) {
13         invertNode(root);
14         return root;
15     }
16     void invertNode(TreeNode * temp)
17     {
18         if(temp!=NULL)
19         {
20             TreeNode* left=temp->left;
21             TreeNode* right=temp->right;
22             temp->left=right;
23             temp->right=left;
24             invertNode(left);
25             invertNode(right);
26         }
27     }
28 };