Antwort
@Override
public void addFirst(String element) {
SimpleListNode node = head.getNext();
SimpleListNode neu = new SimpleListNode(element, head.getNext(), head);
head.setNext(neu);
if (node != null ) {
node.setLast(neu);
} else {
tail.setLast(neu);
}
}
@Override
public void addLast(String element) {
SimpleListNode node = tail.getLast();
SimpleListNode neu = new SimpleListNode(element, tail, tail.getLast());
tail.setLast(neu);
if (node != null ) {
node.setNext(neu);
} else {
head.setNext(neu);
}