public class DVLListe<T> extends AbstractListe<T> {
	private class Item {
	    public Item prev;
	    public Item next;
	    public T value;
	  }

	  private Item first;
	  private Item last;
	  private int size;

	  public boolean isEmpty() {
	    return first == null;
	  }

	  private Item getItem(int pos) {
	    Item current = first;
	    for (int i = 0; i < pos; ++i) {
	      current = current.next;
	    }
	    return current;
	  }

	  public void add(int pos, T e) {
	    Item item = new Item();
	    item.value = e;
	    item.next = getItem(pos);

	    if (item.next ==  null) {
	      item.prev = last;
	      last = item;
	    }
	    else {
	      item.prev = item.next.prev;
	      item.next.prev = item;
	    }
	    if (item.prev == null) {
	      first = item;
	    }
	    else {
	      item.prev.next = item;
	    }

	    ++size;
	  }

	  private T removeItem(Item item) {
	    if (item.prev == null) {
	      first = item.next;
	    }
	    else {
	      item.prev.next = item.next;
	    }
	    if (item.next == null) {
	      last = item.prev;
	    }
	    else {
	      item.next.prev = item.prev;
	    }
	    return item.value;
	  }

	  public T remove(int pos) {
	    if (isEmpty()) {
	      throw new java.util.NoSuchElementException();
	    }
	    --size;
	    return removeItem(getItem(pos));
	  }

	  public class Iterator implements java.util.Iterator<T> {
	    private Item current;

	    public Iterator() {
	      current = first;
	    }
	    public Iterator(int pos) {
	      current = getItem(pos);
	    }
	    public boolean hasNext() {
	      return current != null;
	    }
	    public T next() {
	      if (!hasNext()) {
	        throw new java.util.NoSuchElementException();
	      }
	      T e = current.value;
	      current = current.next;
	      return e;
	    }
	    public void remove() {
	      if (isEmpty() || current == first) {
	        throw new java.util.NoSuchElementException();
	      }
	      removeItem(current == null ? last : current.prev);
	      --size;
	    }
	  }

	  public Iterator iterator() {
	    return new Iterator();
	  }

	  public Iterator iterator(int pos) {
	    return new Iterator(pos);
	  }

	@Override
	public T get(int pos) {
		if(isEmpty()){
	        throw new java.util.NoSuchElementException();

		}
		return getItem(pos).value;
	}

	@Override
	public T set(int pos, T e) {
		if(getItem(pos) == null){
	        throw new java.util.NoSuchElementException();

		}
		Item item = getItem(pos);
		T e1 = item.value;
		item.value = e;


		return e1;
	}

	@Override
	public int size() {

		return size;
	}

	@Override
	public void addFirst(T e) {
		add(0,e);

	}

	@Override
	public void addLast(T e) {
		 add(size(),e);

	}

	@Override
	public T removeFirst() {
		if(isEmpty()){
			throw new java.util.NoSuchElementException();
		}
		T e = remove(0);

		return e;
	}

	@Override
	public T removeLast() {
		if(isEmpty()){
			throw new java.util.NoSuchElementException();
		}
		T e = remove(size()-1);

		return e;
	}

	@Override
	public T getFirst() {
		if(isEmpty()){
			throw new java.util.NoSuchElementException();
		}
		return getItem(0).value;
	}

	@Override
	public T getLast() {
		if(isEmpty()){
			throw new java.util.NoSuchElementException();
		}
		return getItem(size()-1).value;
	}

	@Override
	public T setFirst(T e) {
		if(isEmpty()){
			throw new java.util.NoSuchElementException();
		}

		Item item = getItem(0);
		T e1 = item.value;
		item.value = e;

		return e1;
	}

	@Override
	public T setLast(T e) {
		if(isEmpty()){
			throw new java.util.NoSuchElementException();
		}

		Item item = getItem(size()-1);
		T e1 = item.value;
		item.value = e;
		return e1;
	}
}