class Solution {
public:
    void Mirror(TreeNode *pRoot) {
        if(pRoot == nullptr)
            return;
        TreeNode *p = pRoot->left;
        pRoot->left = pRoot->right;
        pRoot->right = p;
        Mirror(pRoot->left);
        Mirror(pRoot->right);
    }
};

public class Solution {
    public void Mirror(TreeNode root) {
        if(root == null)
            return;
        TreeNode temp = root.left;
        root.left = root.right;
        root.right = temp;
        Mirror(root.left);
        Mirror(root.right);
    }
}