Question

Circle Game Sheila is a naughty girl. Yesterday she came up with a boring game and forced other classmates to play with her. The rule is simple. Some classmates will form a circle initially. Each classmate will be identified by a tag (an integer). Unluckily, you are chosen to be the judge of this game and answer Sheila's queries. Sheila will give the following types of orders: 1. Student with tag T is added to the circle. 2. Remove a student from the circle 3. Do the query on current circle. Please use c++ and write a class to implement linked list for this problem and do not use the libraries <list> <vector> etc. Input The input consists of a single test case. The first line contains an integer N (1N<1000) indicating the initial number of students in the circle. Then follows N integers indicating the tags of the N students in clockwise direction. The circle begins with the first number in the sequence. Then there is an integer Q(1Q100) denoting the number of operations. Initially, the reference point points to the first student, then after each operation, the reference point is updated. There will be 3 kinds of operations in the following format:

Answer 1

Note : Completed as per your requirement... Please run and check with your inputs..

Code:

#include <iostream>
#include <unistd.h>

using namespace std;

struct node
{
   int data;                       //struct to store the data...
   node *next;                  //Pointer to point next cell in a list..
};

class linked_list
{
   private:
       node *head, *tail;
   public:
       linked_list()
       {
           head = NULL;
           tail = NULL;
       }

       int add_node(int n)                      //Func to add initial list elements...
       {

            node *tmp = new node;   //Creating new node...

           tmp->data = n;           //Assigning user entered value to it..
           tmp->next = head;       //Since it is circular list assigning head

           if(head == NULL)
           {
               head = tmp;        //New List...First element..
               tail = head;
           }
           else
           {
               node *temp = new node;   //Create temporary node to traverse list
               temp = head;
               while( temp != tail)    //Traverse until end of the list
               {
                   temp = temp->next;   //Point to next cell
               }
               temp->next = tmp;       //Add at the end of the list..
               tail = tmp;               //Assigning temp to tail..
           }
        tail->next = head;      //Since circular list always make tail's next to point head..
       return 0;
       }
      
       int add_nodeAtPosition(int position, int value, int no, int *ref) //Tag 1 func call...
       {
           node *newnode = new node;       //Creating new node...
           newnode->data = value;           //Assigning user entered value to it..
           newnode->next = NULL;          
  
           if(head == NULL)               //Validating list...
           {      
               cout<<"\n\t<--Head null-->\n";
               head = newnode;            //If list is empty assign new node to head..
           }
           else if (position > no) {
               cout<<"\n\t<--Position out of range-->\n"; //Invalid position entered by user..
               return 0;
           }
           else{

               node *temp1 = head;
               node *temp2 = head;

               while(--position) {           //Make it to point the exact poisition entered by user..      
                   temp1 = temp1->next;   //Point to next cell
                   temp2 = temp2->next;
                   (*ref)++;               //Refernce value to update the reference position...
               }  
               newnode -> next = temp2 -> next; //Inserting new node...          
               temp1->next = newnode;              //Please understand this by analysing this..  
               (*ref)++;
           }

       return 0;
       }

       int deleteAtPosition(int position, int no, int *ref)
       {
              
           if(head == NULL)               //Validating list...
           {
               cout<<"\n\t<--List empty-->\n";
               return 0;
           }
           else if (position > no) {       //Invalid position entered by user..
               cout<<"\n\t<--Position out of range-->\n";
               return 0;
           }
           else{
               (*ref) = 1;
               node *temp1 = new node;       //Temporary nodes to traverse list..
               node *temp = new node;
               temp = head;
              
               if (position == 1){           //Delete at begining...
                   temp = head;
                   tail->next = head -> next;   
                   head = head->next;
                   delete temp;
                   return 0;
               }
               else
               {
                   --position;              //Make position value to point exactly where the user entered..  
                   while(--position) {
                       temp = temp->next;
                       (*ref)++;
                   }
                   temp1 = temp-> next;
                   temp -> next = temp -> next -> next;
                   delete temp1;        //Free the memory...
                   (*ref)++;  
               }
           }
       return 0;
       }

       int updateReference(int *ref) {        //Func to update the refernce pointer...
          
           int pos = 1;
           node *temp = new node;
           temp = head;
           while(pos != *(ref)) {           //Traverse untill the refernce index and stop traversal..  
               temp = temp->next;
               pos++;
           }
           head = temp;                   //make head to point the refernce index...
          
           while(tail->next != head) {      
               tail = tail->next;           //Make tail to point the index before head..
           }  
           (*ref) = 1;
       return 0;
       }  
      
       int display_node(int position, int *ref) { //Tag 3
          
           node *temp = new node;
           temp = head;
           (*ref) = 1;
           while(--position) {               //Point to the position entered b user...
               temp = temp->next;
               (*ref)++;                   //Increment the index of the refernce position also..
           }  
           cout<<"\n\t"<<temp->data<<"\n"; //Display the value in the index...
       return 0;
       }

   /*   int disp_node() {
           node *temp = new node;
           temp = head;
           cout<<"\t";
           do{
               cout<<temp->data<<"-->";
               temp = temp->next;
           }while(temp != head);
           cout<<endl<<endl;
       return 0;
       }
   */
};

int main()
{
   linked_list a;
   static int ref = 1;
   int no, value;
   int i = 0;
   int tags;
   int nop;
   int pos = 1;
   cin>>no;           //Total no of elements..
  
   for(i = 0; i < no; i++) { //Adding initial elements...
       cin>>value;
       a.add_node(value);
   }
   a.disp_node();
   cin>>nop;
   
   while(nop--)
   {
       cin>>tags>>pos;   //Tags and ith postition..
       if (tags == 1) {
          
           cin>>value;        //Value to be inserted...

           //cout<<"\n\tAfter inserting value : "<<endl;  
           a.add_nodeAtPosition(pos, value, no, &ref);
           //a.disp_node();
           a.updateReference(&ref);
           //cout<<"\n\tAfter refernce position update : "<<endl;  
           //a.disp_node();
       }
       else if(tags == 2) {
                  
           a.deleteAtPosition(pos,no, &ref);
           a.updateReference(&ref);
           //cout<<"\n\tAfter refernce position update : "<<endl;  
           //a.disp_node();
       }
       else if(tags == 3) {

           a.display_node(pos, &ref);
           a.updateReference(&ref);
           //cout<<"\n\tAfter refernce position update : "<<endl;  
           //a.disp_node();
       }
       else
           cout<<"\nInvalid tags.."<<endl;
   }
   return 0;
}

Output:

       

Output 2: (as per you required..)

       

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