#include <iostream>
using namespace std;

struct node {
    int info;
    node *next;
};

struct SinglyLinkedCircularList {
    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->next = NULL;

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

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

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

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

    void deleteBack() {
        if(head != NULL) {
            if(head->next == head) {
                delete head;
                head = NULL;
                tail = NULL;
            }
            else {
                node * tmp = head;
                while(tmp->next != tail) {
                    tmp = tmp->next;
                }
                delete tail;
                tail = tmp;
                tail->next = head;
            }
        }
    }

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

                while(tmp != NULL && tmp->info != x) {
                    prev = tmp;
                    tmp = tmp->next;
                }

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

            }
        }
    }

    void deleteNode(node * x) {
        if(head != NULL) {
            if(head == x) {
                deleteFront();
            }
            else {
                node * tmp = head;
                node * prev = NULL;

                while(tmp != NULL && tmp != x) {
                    prev = tmp;
                    tmp = tmp->next;
                }

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

            }
        }
    }

    void print() {
        node * tmp = head;
        for(int i = 0; i < 10; i++) {
            cout << tmp->info << " --> ";
            tmp = tmp->next;
        }
        cout << endl;
    }
};


int main() {

    SinglyLinkedCircularList slcl;
    slcl.init();

    slcl.insertFront(1);
    slcl.insertFront(2);

    slcl.insertBack(3);
    slcl.insertBack(4);



    slcl.deleteNode(1);
    slcl.print();
    return 0;
}