ListSerialize (C++)

Task:

Serialize and deserialize double-linked list with random access links.

pseudo:

 Node  
 {  
    Node* next;  
    Node* prev;  
    Node* rand;  
    string data;  
 }  
 List  
 {  
    Node* Head;  
    Node* Tail;  
    int Count;  
  }  

Complexity requirement: less than n^2