剑指offer -- 二叉树的镜像

struct TreeNode {
    int val;
    struct TreeNode *left;
    struct TreeNode *right;
    TreeNode(int x) :
            val(x), left(NULL), right(NULL) {
    }
};
class Solution {
public:
    void Mirror(TreeNode *pRoot) {
        if(pRoot==NULL||(pRoot->right==NULL&&pRoot->left==NULL))
            return ;
        struct TreeNode *temp=pRoot->left;
        pRoot->left=pRoot->right;
        pRoot->right=temp;
        
        if(pRoot->left){
           Mirror(pRoot->left);
        }
          if(pRoot->right){
           Mirror(pRoot->right);
        }    
    }
};