/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* struct TreeNode *left;
* struct TreeNode *right;
* };
*/
struct TreeNode* mirrorTree(struct TreeNode* root){
struct TreeNode *t;
if(root==NULL) return root;
t=root->left;
root->left=root->right;
root->right=t;
mirrorTree(root->left);
mirrorTree(root->right);
return root;
}
