package Problema3;

import java.util.Iterator;

public class LinkedList<T> {
    private static class Node<T> {
        T value;
        Node<T> next;

        Node(T value) {
            this.value = value;
            this.next = null;
        }

        Node(T value, Node<T> nextNode) {
            this.value = value;
            this.next = nextNode;
        }
    }

    public class ListIterator implements Iterator<T> {
        Node<T> iterator = LinkedList.this.first;

        @Override
        public boolean hasNext() {
            return iterator != null;
        }

        @Override
        public T next() {
            Node<T> prv = iterator;
            iterator = iterator.next;

            return prv.value;
        }
    }

    Node<T> first, last;

    //Insereaza un nod la inceputul listei
    public void addFirst(T data) {
        Node<T> newNode = new Node<T>(data);
        if (this.first == null && this.last == null) {
            this.first = newNode;
            this.last = newNode;
            return;
        }
        newNode.next = this.first;
        this.first = newNode;
    }
    //Insereaza un nod la sfarsitul listei
    public void add(T data) {
        Node<T> newNode = new Node<T>(data);
        if (this.first == null && this.last == null) {
            this.first = newNode;
            this.last = newNode;
            return;
        }
        last.next = newNode;
        this.last = newNode;
    }
    //Returneaza primul nod din lista
    public T getNode() {
        return this.first.value;
    }
    //Returneaza un obiect de tip ListIterator
    public Iterator<T> iterator() {
        return new ListIterator();
    }
}