linked_list.java

class Node {
    int data;
    Node next;

    Node(int data) {
        this.data = data;
        this.next = null;
    }
}

class LinkedList {
    private Node head;

    public void insert(int data) {
        Node newNode = new Node(data);
        if (head == null) {
            head = newNode;
        } else {
            Node current = head;
            while (current.next != null) {
                current = current.next;
            }
            current.next = newNode;
        }
    }

    public void delete(int key) {
        if (head == null) return;

        if (head.data == key) {
            head = head.next;
            return;
        }

        Node current = head;
        while (current.next != null) {
            if (current.next.data == key) {
                current.next = current.next.next;
                return;
            }
            current = current.next;
        }
    }

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

    public static void main(String[] args) {
        LinkedList list = new LinkedList();
        list.insert(10);
        list.insert(20);
        list.insert(30);
        
        System.out.println("Linked List:");
        list.display();
        
        list.delete(20);
        
        System.out.println("After deleting 20:");
        list.display();
    }
}