#include <iostream>
using namespace std;
const int MAX_SIZE = 100;
struct node {
    int info;
    node * prev, * next;
};

struct DoublyLinkedCircularList {
    node * head;
    node * tail;

    void init() {
        head = NULL;
        tail = NULL;
    }

    void insertFront(int x) {
        node * new_node = new node;
        new_node->info = x;
        new_node->prev = NULL;
        new_node->next = NULL;

        if(head == NULL) {
            head = new_node;
            tail = head;
            tail->next = head;
            head->prev = tail;
        }
        else {
            new_node->next = head;
            head->prev = new_node;
            head = new_node;
            tail->next = head;
            head->prev = tail;
        }
    }

    void insertBack(int x) {
        node * new_node = new node;
        new_node->info = x;
        new_node->prev = NULL;
        new_node->next = NULL;


        if(head == NULL) {
            head = new_node;
            tail = head;
            tail->next = head;
            head->prev = tail;
        }
        else {
            tail->next = new_node;
            new_node->prev = tail;
            tail = new_node;
            tail->next = head;
            head->prev = tail;
        }
    }

    void deleteFront() {
        if(head != NULL) {
            if(head->next == tail) {
                delete head;
                head = NULL;
                tail = NULL;
            }
            else {
                head = head->next;
                delete head->prev;
                head->prev = tail;
                tail->next = head;
            }
        }
    }

    void deleteBack() {
        if(head != NULL) {
            if(head->next == tail) {
                delete head;
                head =  NULL;
                tail = NULL;
            }
            else {
                tail = tail->prev;
                delete tail->next;
                tail->next = head;
                head->prev = tail;

            }
        }
    }

    void deleteAll() {
        while(head != NULL) {
            deleteBack();
        }
    }


    void deleteNode(int x) {
        if(head != NULL) {
            if(head->info == x) {
                deleteFront();
            }
            else {
                node * tmp = head;
                while(tmp->info != x) {
                    tmp = tmp->next;
                }

                if(tmp == tail) {
                    deleteBack();
                }
                else {
                    tmp->next->prev = tmp->prev;
                    tmp->prev->next = tmp->next;
                }
            }

        }
    }

    void deleteNode(node *  x) {
        if(head != NULL) {
            if(head == x) {
                deleteFront();
            }
            else {
                node * tmp = head;
                while(tmp != x) {
                    tmp = tmp->next;
                }

                if(tmp == tail) {
                    deleteBack();
                }
                else {
                    tmp->next->prev = tmp->prev;
                    tmp->prev->next = tmp->next;
                    delete tmp;
                }
            }

        }
    }
    void print() {
        node * tmp = head;
        while(tmp != tail) {
            cout << tmp->info << " <--> ";
            tmp = tmp->next;
        }
        cout << tmp->info << " <--> ";
        tmp = tmp->next;

        while(tmp != tail) {
            cout << tmp->info << " <--> ";
            tmp = tmp->next;
        }
        cout << tmp->info << endl;

        while(tmp != head) {
            cout << tmp->info << " <--> ";
            tmp = tmp->prev;
        }
        cout << tmp->info << " <--> ";
        tmp = tmp->prev;
        while(tmp != head) {
            cout << tmp->info << " <--> ";
            tmp = tmp->prev;
        }
        cout << tmp->info << endl;
    }
};
 int main() {

     DoublyLinkedCircularList dlcl;
     dlcl.init();
     dlcl.insertFront(1);
     dlcl.insertFront(2);
     dlcl.insertFront(3);
     dlcl.insertBack(4);
     dlcl.insertBack(5)

     ;


     dlcl.print();

     cout << endl;
     dlcl.deleteBack();
     dlcl.deleteFront();

     dlcl.print();
    return 0;
}