Class LL

12_LinkedList.java/LL.java:1–343

public class LL {
    public static class Node {
        int data;
        Node next;
        public Node(int data) {
            this.data = data;
            this.next = null;
        }
    }
    public static Node head;
    public static Node tail;
    public static int size;

    public void addFirst(int data) {
        size++;
        Node newNode = new Node(data);
        if(head == null) {
            head = tail = newNode;
        } else {
            newNode.next = head;
            head = newNode;
        }
    }

    public void addLast(int data) {
        size++;
        Node newNode = new Node(data);
        if(head == null) {
            head = tail = newNode;
        } else {
            tail.next = newNode;
            tail = newNode;
        }
    }

    public void print() {
        Node temp = head;
        while(temp != null) {
            System.out.print(temp.data+"->");
            temp = temp.next;
        }
        System.out.println("null");
    }

    public void add(int idx, int data) {
        if(idx == 0) {
            addFirst(data);
            return;
        }
        size++;
        Node temp = head;
        int i = 0;
        while(temp != null) {
            if(i == idx-1) {//add here
                Node newNode = new Node(data);
                //insertion at middle
                newNode.next = temp.next;
                temp.next = newNode;
                return;
            }