Deletion in Circular Linked List

February 21, 2023

&& operator in C

JAVA Program to Delete a Node of a Circular Linked List

A Circular Linked List is collection of data elements where each element points towards the next element and the last Element points towards the First Element Hence forming  a Loop.            Below on this page we will learn about Circular Linked List Deletion in java.

Algorithm for deletion from beginning of a circular linked list

  • deleteFirst()
  • IF head == null
    • return
  • ELSE IF head != tail
    • head = head -> next
    • tail -> next = head
  • ELSE
    • head = tail = null
Deletion in circular Linked List from Beginning 
public void deleteFirst() {  
        if(head == null) {  
            return;  
        }  
        else {  
            if(head != tail ) {  
                head = head.next;  
                tail.next = head;  
            }  
            else {  
                head = tail = null;  
            }  
        }  
    }

Algorithm for deletion from last of a circular linked list

  • 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
Deletion from last in Singly Linked List 
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;
            }
        }
    }
DSA desktop gif
DSA mobile gif

Deletion from beginning in Circular Linked List

Sorted Insert In Circular Linked List

Insertion and Deletion in a Circular Linked List

Split a Circular Linked List in two halves

Count nodes in Circular Linked List

Algorithm for deletion from last of a circular linked list

  • deleteLast()
  • IF head == null
    • return
  • ELSE
    • WHILE (–n>0)
      • previous = temp;
      • temp = temp.next;
    • previous.next = temp.next;
Deletion in circular Linked List from Nth node

Code for deletion of a node in circular Linked List in Java

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
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 Prime

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

Get Prime
Course List
Course List

Checkout list of all the video courses in PrepInsta Prime Subscription

Checkout list of all the video courses in PrepInsta Prime Subscription

Checkout
Checkout

Circular Linked List

  • Introduction to Circular Linked List
    Click Here
  • Circular Linked List Applications
    Click Here
  • Circular Linked List in –
    C | C++ | Java
  • Insertion in Circular Linked List –
    C | C++ | Java
  • Insertion at the beginning–
    C | C++ | Java
  • Insertion at the end –
    C | C++ | Java
  • Insertion at nth position –
    C | C++ | Java
  • Deletion in Circular Linked List –
    C | C++ | Java
  • Deletion from beginning in Circular Linked List –
    C | C++ | Java
  • Deletion from nth position in Circular Linked List –
  • Deletion from end in Circular Linked List –
    C | C++ | Java
  • Insertion and Deletion in 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

Circular Linked List