/*
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) {  //一个函数就够
     if(pRoot==nullptr)
     return;           
      if(pRoot->left==nullptr&&pRoot->right==nullptr )//左右都是空节点以及到头了
     return;
   
       TreeNode *temp=pRoot->left;
        pRoot->left= pRoot->right;   
       pRoot->right=temp;
      
        if(pRoot->left!=nullptr)
        Mirror(pRoot->left); 
       
        if(pRoot->right!=nullptr)
         Mirror(pRoot->right);    
    }
    
};