leetcode 226_invertbinarytree

 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    TreeNode* (TreeNode* root) {
        if(root){
            TreeNode*rleft = invertTree(root->right);
            root->right = invertTree(root->left);
            root->left = rleft;
        }
        return root;
    }
};