/*
* Remove the nth element in the list. The first element is element 1.
* Return the removed element to the caller.
*/
public E remove(int n) {
LinkEntry<E> le = new LinkEntry<E>();
le = head;
if (n == 1) {
if (size() == 1) {
head = tail = null;
return le.element;
} else {
head = head.next;
head.previous = null;
return le.element;
}
} else if (n == size()) {
le = tail;
tail = tail.previous;
tail.next = null;
return le.element;
} else {
for (int i = 1; i < n; i++) le = le.next;
le.previous.next = le.next;
le.next.previous = le.previous;
return le.element;
}
}
/*
* Add e to the end of the doubly linked list.
* Returns true - if e was successfully added, false otherwise.
*/
public boolean add(E e) {
int length = size();
LinkEntry<E> le = new LinkEntry<E>();
le.element = e;
if (head == null) head = tail = le;
else {
tail.next = le;
le.previous = tail;
tail = le;
}
if (size() - length == 1) return true;
else return false;
}
