Programming
Aptitude
Syllabus
Interview Preparation
Interview Exp.
Off Campus
Circular Linked List Insertion and Deletion in Java
Java Program for Ciruclar Linked List Insertion and Deletion
We will look at different ways to do insertion or deletion in a circular linked list in Java at different possible positions.
What is a Circular Linked List
A circular Linked list is a connected series of nodes. Where each node has a data value and a next pointer.
The next reference for each node has the location of the next node.
The first node in the circular linked list is called the head node and the last node (sometimes referred to as the tail node) has the address of the first node.
Thus making whole connected nodes circular in nature.
- Head – The first node in Circular Linked List
- Next – Has the location for the next node in the circular linked list
- Data – Part of the node that stores the actual data value
- Node – Combination of Data value and next
Some variations of the Circular linked list may also require storing the tail along with the head. The tail tells us where the circular linked list is ending.
Structure of a Linked Circular List in Java
Below is the structure –
// Node Class
class Node{
int data;
Node next;
Node(int x) // parameterized constructor
{
data = x;
next = null;
}
}
Insertion in a Circular Linked List in Java
We can do insertion at the following –
- At Start
- At end
- After a node
We will code for all three possibilities –
Method 1
Run
import java.lang.*;
public class Main {
public static void main(String[] args) {
Main Obj = new Main();
Obj.insertBegin(11);
Obj.insertBegin(22);
Obj.insertEnd(33);
Obj.insertEnd(44);
Obj.insertAfter(3,77);
Obj.print();
}
public class Node{
int element;
Node next;
public Node(int element) {
this.element = element;
}
}
public Node head = null;
public Node tail = null;
int size=0;
public void insertBegin(int element){
Node newEle = new Node(element);
if(head == null) {
head = newEle;
tail = newEle;
newEle.next = head;
}
else {
newEle.next=head;
head=newEle;
tail.next = head;
}
size++;
}
public void insertEnd(int element){
Node newEle = new Node(element);
if(head == null) {
head = newEle;
tail = newEle;
newEle.next = head;
}
else {
tail.next=newEle;
newEle.next=head;
tail=newEle;
}
size++;
}
public void insertAfter(int n,int data)
{
int size = calcSize(head);
// Can only insert after 1st position
// Can't insert if position to insert is greater than size of Linked List
if(n < 1 || n > size)
{
System.out.println("Can't insert\n");
}
else
{
Node newNode = new Node(data);
// required to traverse
Node temp = head;
// traverse to the nth node
while(--n > 1)
temp=temp.next;
newNode.next= temp.next;
temp.next = newNode;
}
}
public int calcSize(Node node){
int size = 0;
while(node!=tail){
node = node.next;
size++;
}
return size+1;
}
public void print() { //print function
Node current = head;
if(head == null) {
System.out.println("List is empty");
}
else {
System.out.println("Nodes of the circular linked list: ");
do{
System.out.print(" "+ current.element);
current = current.next;
}while(current != head);
System.out.println();
}
}
}
Output
Insertion at Beginning : 22 11 Insertion at End : 22 11 33 44 Insertion after 2nd position 44 22 77 11 33
Method 2
Run
import java.lang.*;
public class Main {
public static void main(String[] args) {
Main Obj = new Main();
Obj.insertBegin(11);
Obj.insertBegin(22);
System.out.println("Insertion at Beginning : ");
Obj.print();
Obj.insertEnd(33);
Obj.insertEnd(44);
System.out.println("Insertion at End :" );
Obj.print();
Obj.insertAfterPosition(2,77);
System.out.println("Insertion after 2nd position");
Obj.print();
}
public class Node{
int element;
Node next;
Node prev;
public Node(int element) {
this.element = element;
}
}
public Node head = null;
public Node tail = null;
int size=0;
public void insertBegin(int element){
Node newEle = new Node(element);
if(head == null) {
head = newEle;
tail = newEle;
newEle.next = head;
newEle.prev=head;
}
else {
head.prev = newEle;
newEle.prev=tail;
newEle.next = head;
tail.next = newEle;
head=newEle;
}
size++;
}
public void insertEnd(int element){
Node newEle=new Node(element);
if(head == null) {
head = newEle;
tail = newEle;
newEle.next = head;
newEle.prev=head;
}
else{
tail.next=newEle;
newEle.next=head;
newEle.prev=tail;
head.prev=newEle;
tail=newEle;
}
}
public void insertAfterPosition(int n, int data) {
int len = getLength();
// if insertion position is 0 means entering at start
if (n == 0) {
insertBegin(data);
return;
}
// means inserting after last item
if (n == len) {
insertEnd(data);
return;
}
// else insertion will happen somewhere in the middle
if (n < 1 || len < n) System.out.println("Invalid position");
else { Node freshNode = new Node(data);
// can remove null assignments also (constructor takes care of these)
// added just for explanation purpose
freshNode.next = null;
freshNode.prev = null;
// nthNode used to traverse the Linked List
Node nthNode = head;
// traverse till the nth node
while (--n > 0) {
nthNode = nthNode.next;
}
Node nextNode = nthNode.next; // (n+1)th node
// assigning (n+1)th node's previous to this new node
nextNode.prev = freshNode;
// new_node's next assigned to (n+1)th node
freshNode.next = nextNode;
// new_node's previous assigned to nth node
freshNode.prev = nthNode;
// assign nth node's next to new_node
nthNode.next = freshNode;
}
}
public int getLength() {
int size = 0;
Node temp=head;
// traverse to the last node each time incrementing the size
while (temp != tail) {
temp = temp.next;
size++;
}
return size;
}
public void print() { //print function
Node current = head;
if(head == null) {
System.out.println("List is empty");
}
else {
do{
System.out.print(" "+ current.element);
current = current.next;
}while(current != head);
System.out.println();
}
}
}
Output
Insertion at Beginning : 22 11 Insertion at End : 22 11 33 44 Insertion after 2nd position 44 22 77 11 33
Deletion in a Circular Linked List in Java
We can do deletion at the following –
- At Start
- At end
- Deleting nth node
We will code for all three possibilities –
Method 1
Run
import java.util.*;
public class Main {
public static void main(String[] args) {
Main Obj = new Main();
Obj.add(10);
Obj.add(20);
Obj.add(30);
Obj.add(40);
Obj.add(50);
Obj.add(60);
System.out.println("List Before Deletion");
Obj.print();
System.out.println("List After Deleting first node");
Obj.deleteFirst();
Obj.print();
System.out.println("List After Deleting last node");
Obj.deleteLast();
Obj.print();
Obj.deleteNthNode(2);
System.out.println("List After Deleting 2nd node");
Obj.print();
}
public class Node{
int element;
Node next;
public Node(int element) {
this.element = element;
}
}
public Node head = null;
public Node tail = null;
public void print() {
Node temp = head;
if(head == null) {
System.out.println("null");
}
else {
do{
System.out.print(" "+ temp.element);
temp = temp.next;
}while(temp != head);
System.out.println();
}
}
public void add(int element){
Node newNode = new Node(element);
if(head == null) {
head = newNode;
tail = newNode;
newNode.next = head;
}
else {
tail.next = newNode;
tail = newNode;
tail.next = head;
}
}
public void deleteFirst() {
if(head == null) {
return;
}
else {
if(head != tail ) {
head = head.next;
tail.next = head;
}
else {
head = tail = null;
}
}
}
public void deleteLast() {
if(head == null) {
return;
}
else {
if(head != tail ) {
Node current = head;
while(current.next != tail) {
current = current.next;
}
tail = current;
tail.next = head;
}
else {
head = tail = null;
}
}
}
public int calcLen(){
int len = 0;
Node temp=head;
while(temp!=tail){
temp = temp.next;
len++;
}
return len;
}
public void deleteNthNode(int n)
{
int len = calcLen();
// Can only insert after 1st position
// Can't insert if position to insert is greater than size of Linked List
if(n < 1 || n > len)
{
System.out.println("Can't delete\n");
}
else
{
if(n == 1)
{
head = head.next;
return;
}
// required to traverse
Node temp = head;
Node previous = null;
// traverse to the nth node
while(--n > 0) {
previous = temp;
temp = temp.next;
}
// assigned next node of the previous node to nth node's next
previous.next = temp.next;
System.out.println("Deleted: " + temp.element);
}
}
}
Output
List Before Deletion 10 20 30 40 50 60 List After Deleting first node 20 30 40 50 60 List After Deleting last node 20 30 40 50 Deleted: 30 List After Deleting 2nd node 20 40 50
Method 2
Run
import java.lang.*;
public class Main {
public static void main(String[] args) {
Main Obj = new Main();
Obj.add(10);
Obj.add(20);
Obj.add(30);
Obj.add(40);
Obj.add(50);
Obj.add(60);
System.out.println("List Before Deletion");
Obj.print();
System.out.println("List After Deleting first node");
Obj.deleteFirst();
Obj.print();
System.out.println("List After Deleting last node");
Obj.deleteLast();
Obj.print();
Obj.deletenth(2);
System.out.println("List After Deleting 2nd node");
Obj.print();
}
public class Node{
int element;
Node next;
Node prev;
public Node(int element) {
this.element = element;
}
}
public Node head = null;
public Node tail = null;
public void print() {
Node temp = head;
if(head == null) {
System.out.println("null");
}
else {
do{
System.out.print(" "+ temp.element);
temp = temp.next;
}while(temp != head);
System.out.println();
}
}
public void add(int element){
Node newNode = new Node(element);
if(head == null) {
head = newNode;
tail = newNode;
newNode.next = head;
newNode.prev=head;
}
else {
tail.next = newNode;
newNode.prev=tail;
tail = newNode;
tail.next = head;
}
}
public int Length(Node head)
{
Node current = head;
int count = 0;
// if list is empty
// simply return length zero
if (head == null)
{
return 0;
}
// traverse forst to last node
else
{
do
{
current = current.next;
count++;
} while (current != head);
}
return count;
}
public void deleteFirst() {
if(head == null) {
return;
}
else {
if(head != tail ) {
head = head.next;
tail.next = head;
}
else {
head = tail = null;
}
}
}
public void deleteLast() {
if(head == null) {
return;
}
else {
if(head != tail ) {
Node current = head;
while(current.next != tail) {
current = current.next;
}
tail = current;
tail.next = head;
head.prev=tail;
}
else {
head = tail = null;
}
}
}
public void deletenth (int n)
{
if (head == null)
{
return;
}
else
{
Node current = head;
int pos = n;
for (int i = 1; i < pos; i++)
{
current = current.next;
}
if (current == head)
{
head = current.next;
}
else if (current == null)
{
current = current.prev;
}
else
{
current.prev.next = current.next;
current.next.prev = current.prev;
}
//Delete the middle node
current = null;
}
}
void printList ()
{
//Node current will point to head
Node curr = head;
if (head == null)
{
System.out.println ("List is empty");
return;
}
while (curr != null)
{
//Prints each node by increasing order of the pointer
System.out.print (curr.element + " ");
curr = curr.next;
}
System.out.println ();
}
}
Output
List Before Deletion 10 20 30 40 50 60 List After Deleting first node 20 30 40 50 60 List After Deleting last node 20 30 40 50 List After Deleting 2nd node 20 40 50
Prime Course Trailer
Related Banners
Get PrepInsta Prime & get Access to all 200+ courses offered by PrepInsta in One Subscription
Get over 200+ course One Subscription
Courses like AI/ML, Cloud Computing, Ethical Hacking, C, C++, Java, Python, DSA (All Languages), Competitive Coding (All Languages), TCS, Infosys, Wipro, Amazon, DBMS, SQL and others
Circular Linked List
- Introduction to Circular Linked List
Click Here - Circular Linked List Applications
Click Here - Circular Linked List in –
- Insertion in Circular Linked List –
- Insertion at the beginning–
- Insertion at the end –
- Insertion at nth position –
- Deletion in Circular Linked List –
- Deletion from beginning in Circular Linked List –
- Deletion from nth position in Circular Linked List –
- Deletion from end in Circular Linked List –
- Insertion and Deletion in Circular Linked List – C | C++ | Java
- Split a Circular Linked List in two halves –
- Count nodes in Circular Linked List –
- Sorted Insert In Circular Linked List –
- Insertion in the middle in Circular Linked List –
Circular Linked List
- Introduction to Circular Linked List
- Circular Linked List Applications
- Circular Linked List in – C | C++ | Java
- Insertion in Circular Linked List – C | C++ | Java
- Deletion in Circular Linked List – C | C++ | Java
- Insertion and Deletion in a Circular Linked List – C | C++ | Java
- Split a Circular Linked List in two halves – C | C++ | Java
- Count nodes in Circular Linked List – C | C++ | Java
- Sorted Insert In Circular Linked List – C | C++ | Java
- Insertion in the middle in Circular Linked List – C | C++ | Java
Login/Signup to comment