vasav1

public class LinkedList {

    private Node head;
    private Node tail;
    private int length;

    class Node {
        int value;
        Node next;

        Node(int value) {
            this.value = value;
        }
    }

    public LinkedList(int value) {
        Node newNode = new Node(value);
        head = newNode;
        tail = newNode;
        length = 1;
    }

    public Node getHead() {
        return head;
    }

    public Node getTail() {
        return tail;
    }

    public int getLength() {
        return length;
    }

    public void printList() {
        Node temp = head;
        while (temp != null) {
            System.out.println(temp.value);
            temp = temp.next;
        }
    }

    public void printAll() {
        if (length == 0) {
            System.out.println("Head: null");
            System.out.println("Tail: null");
        } else {
            System.out.println("Head: " + head.value);
            System.out.println("Tail: " + tail.value);
        }
        System.out.println("Length:" + length);
        System.out.println("\nLinked List:");
        if (length == 0) {
            System.out.println("empty");
        } else {
            printList();
        }
    }
    
    public void makeEmpty() {
        head = null;
        tail = null;
        length = 0;
    }

    public void append(int value) {
        Node newNode = new Node(value);
        if (length == 0) {
            head = newNode;
            tail = newNode;
        } else {
            tail.next = newNode;
            tail = newNode;
        }
        length++;
    }

    public Node removeLast() {
        if (length == 0) return null;
        Node temp = head;
        Node pre = head;
        while(temp.next != null) {
            pre = temp;
            temp = temp.next;
        }
        tail = pre;
        tail.next = null;
        length--;
        if (length == 0) {
            head = null;
            tail = null;
        }
        return temp;
    }

    public void prepend(int value) {
        Node newNode = new Node(value);
        if (length == 0) {
            head = newNode;
            tail = newNode;
        } else {
            newNode.next = head;
            head = newNode;
        }
        length++;
    }

    public Node removeFirst() {
        if (length == 0) return null;
        Node temp = head;
        head = head.next;
        temp.next = null;
        length--;
        if (length == 0) {
            tail = null;
        }
        return temp;
    }

    public Node get(int index) {
        if (index < 0 || index >= length) return null;
        Node temp = head;
        for(int i = 0; i < index; i++) {
            temp = temp.next;
        }
        return temp;
    }

    public boolean set(int index, int value) {
        Node temp = get(index);
        if (temp != null) {
            temp.value = value;
            return true;
        }
        return false;
    }

    public boolean insert(int index, int value)  {
        if (index < 0 || index > length) return false;
        if (index == 0) {
            prepend(value);
            return true;
        }
        if (index == length) {
            append(value);
            return true;
        }
        Node newNode = new Node(value);
        Node temp = get(index - 1);
        newNode.next = temp.next;
        temp.next = newNode;
        length++;
        return true;
    }

    public Node remove(int index) {
        if (index < 0 || index >= length) return null;
        if (index == 0) return removeFirst();
        if (index == length - 1) return removeLast();

        Node prev = get(index - 1);
        Node temp = prev.next;

        prev.next = temp.next;
        temp.next = null;
        length--;
        return temp;
    }

	public void reverse(){
	    Node temp = head;
	    head=tail;
	    tail=temp;
	    Node after = temp.next;
	    Node before = null;
	    for(int i=0;i<length;i++){
	        after=temp.next;
	        temp.next=before;
	        before=temp;
	        temp=after;
	    }
	}

}

public class Main {

    public static void main(String[] args) {

        LinkedList myLinkedList = new LinkedList(4);
        
        myLinkedList.printAll();
        myLinkedList.makeEmpty();
        myLinkedList.append(1);
        myLinkedList.append(2);
         System.out.println(myLinkedList.removeLast().value);
         System.out.println(myLinkedList.removeLast().value);
         System.out.println(myLinkedList.removeLast());
        System.out.println("Before prepend():");
        System.out.println("-----------------");
        myLinkedList.printAll();

        myLinkedList.prepend(1);

        System.out.println("\n\nAfter prepend():");
        System.out.println("----------------");
        myLinkedList.printAll();
        System.out.println(myLinkedList.removeFirst().value);
        System.out.println(myLinkedList.removeFirst().value);
        System.out.println(myLinkedList.removeFirst());
        System.out.println(myLinkedList.get(3).value);
        System.out.println("Linked List before set():");
        myLinkedList.printList();

        myLinkedList.set(2, 99);

        System.out.println("\nLinked List after set():");
        myLinkedList.printList();
        System.out.println("LL before insert():");
        myLinkedList.printList();

        myLinkedList.insert(1, 2);

        System.out.println("\nLL after insert(2) in middle:");
        myLinkedList.printList();

        myLinkedList.insert(0, 0);

        System.out.println("\nLL after insert(0) at beginning:");
        myLinkedList.printList();

        myLinkedList.insert(4, 4);

        System.out.println("\nLL after insert(4) at end:");
        myLinkedList.printList();
          System.out.println("LL before remove():");
        myLinkedList.printList();

        System.out.println("\nRemoved node:");
        System.out.println(myLinkedList.remove(2).value);
        System.out.println("LL after remove() in middle:");
        myLinkedList.printList();

        System.out.println("\nRemoved node:");
        System.out.println(myLinkedList.remove(0).value);
        System.out.println("LL after remove() of first node:");
        myLinkedList.printList();

        System.out.println("\nRemoved node:");
        System.out.println(myLinkedList.remove(2).value);
        System.out.println("LL after remove() of last node:");
        myLinkedList.printList();
         myLinkedList.append(2);
        myLinkedList.append(3);
        myLinkedList.append(4);

        System.out.println("LL before reverse():");
        myLinkedList.printList();

        myLinkedList.reverse();

        System.out.println("\nLL after reverse():");
        myLinkedList.printList();


}
}