class CllNode{

private int data;

private CllNode next;

public CllNode(int data){

this.data = data;

next = null;

}

public int getData(){

return data;

}

public void setData(int data){

this.data = data;

}

public CllNode getNext(){

return next;

}

public void setNext(CllNode node){

this.next = node;

}

}

public class CircularLinkedList{

protected CllNode tail;

protected int length;

public CircularLinkedList(){

tail = null;

length = 0;

}

//add element to the head of the circular list

public void addToHead(int data){

CllNode temp = new CllNode(data);

if(tail == null){

tail = temp;

tail.setNext(tail);

}else{

temp.setNext(tail.getNext());

tail.setNext(temp);

}

length++;

}

//add element to the tail of the list

public void addToTail(int data){

addToHead(data);

tail = tail.getNext();

}

//add element

public void add(int data){

addToHead(data);

}

//peek element at the tail

public int peek(){

return tail.getData();

}

//remove the element from the head

public int removeFromHead(){

CllNode temp = tail.getNext();

if(tail == tail.getNext()){

tail = null;

}else{

tail.setNext(temp.getNext());

temp.setNext(null);

}

length--;

return temp.getData();

}

//remove the element from the tail

public int removeFromTail(){

if(isEmpty()){

return Integer.MIN_VALUE;

}

CllNode temp = tail.getNext();

while(temp.getNext() != tail){

temp = temp.getNext();

}

CllNode tailNode = tail;

if(temp == tail){

tail = null;

}else{

temp.setNext(tailNode.getNext());

tail = temp;

}

length--;

return tailNode.getData();

}

//a boolean to check if list contains the data

public boolean contains(int data){

if(tail == null){

return false;

}

CllNode temp = tail.getNext();

while(temp != tail && (temp.getData() != data)){

temp = temp.getNext();

}

return temp.getData() == data;

}

// to remove the element from the list of specified data

public int remove(int data){

if(tail == null) return Integer.MIN_VALUE;

CllNode temp = tail.getNext();

CllNode previous = tail;

int element;

for(element = 0 ; element < length && (!(temp.getData() == data)) ; element++){

previous = previous.getNext();

temp = temp.getNext();

}

if(temp.getData() == data){

if(tail == tail.getNext()){

tail = null;

}

else{

if(temp == tail){

tail = previous;

previous.setNext(previous.getNext().getNext());

}

}

temp.setNext(null);

length--;

return temp.getData();

}

else return Integer.MAX_VALUE;

}

public int size(){

return length;

}

public int length(){

return length;

}

public boolean isEmpty(){

return tail == null;

}

public String toString(){

if(tail == null){

return "[]";

}

String result = "[";

CllNode temp = tail.getNext();

for(int i = 0 ; i < length ; i++){

result += temp.getData();

if(i < length - 1 ){

result += " , ";

}

temp = temp.getNext();

}

return result;

}

public static void main(String[] args){

CircularLinkedList cll = new CircularLinkedList();

cll.addToHead(10);

cll.addToHead(20);

System.out.println(cll.toString());

cll.addToTail(30);

System.out.println(cll.toString());

cll.removeFromHead();

System.out.println(cll.toString());

cll.removeFromTail();

System.out.println(cll.toString());

cll.addToHead(20);

cll.addToHead(20);

System.out.println(cll.toString());

cll.remove(10);

System.out.println(cll.toString());

}

}