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  1. Prepare
  2. C++
  3. Classes
  4. Abstract Classes - Polymorphism
  5. Discussions

Abstract Classes - Polymorphism

  • itsmekarizma
     + 0 comments

    Here is an easy solution, correctly done, with head, tail, etc. and also deleting the pointers, not simply removing them from the map 'mp':

    class LRUCache:Cache {
public:
LRUCache(int capacity){
      this->cp = capacity;
}
void insert_node(int k, Node* node){
   //Set head
   this->head = node;
   if (mp.empty()) this->tail = node; //Set tail
   else node->next = mp.begin()->second; //Set next node
   
   //Insert new node
   mp.insert(mp.begin(), std::pair<int, Node*>(k, node));
   if (node->next!=nullptr) node->next->prev = node;
}
void set(int k, int v){
   Node* node = new Node(k,v);
   std::map<int, Node*>::iterator duplicate = this->mp.find(k);

   //If key exists
   if(duplicate!=this->mp.end()){

      //Remove old key
      if (node->next!=nullptr) node->next->prev = node->prev;
      if (node->prev!=nullptr){
         node->prev->next = node->next;
         if (node->next==nullptr) this->tail = node->prev;
      }
      delete(mp.at(k));
      mp.erase(k);
      
      //Insert at 0
      insert_node(k, node);
   }
   else {
      //If size is at max capacity
      if(this->mp.size()==this->cp){

         //Remove tail
         if(this->tail->prev!=nullptr) this->tail->prev->next=nullptr;
         delete(this->tail);
         mp.erase(this->tail->key);
      }

      //Insert at 0
      insert_node(k, node);
   }
}
int get(int k) {
   return (this->mp.find(k)!=this->mp.end())? this->mp.at(k)->value : -1;
}
};