/*
* 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;
}
}
public void push(E e) {
LinkEntry<E> temp = new LinkEntry<E>();
temp.element = e;
temp.next = head;
head = temp;
num_elements++;
System.out.println("Element is pushed to Stack List is: " + e);
}
/*
* 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;
}
public boolean add_sorted(E e) {
LinkEntry<E> ne = new LinkEntry<E>();
ne.element = e;
if (head == null && tail == null) {
head = tail = ne;
} else {
LinkEntry<E> prev = null;
LinkEntry<E> temp;
for (temp = head; temp != null; temp = temp.next) {
int comp = ((Comparable) e).compareTo(temp.element);
if (comp < 0) /* Element added is less than one on list. */ {
break;
}
prev = temp;
}
if (prev == null) /* Adding as new head */ {
ne.next = head;
head = ne;
} else if (temp == null) /* Adding as new tail */ {
tail.next = ne;
tail = ne;
} else /* Adding in the middle */ {
ne.next = prev.next; /* HAS TO BE IN THIS ORDER */
prev.next = ne; /* HAS TO BE IN THIS ORDER */
}
}
return true;
}
// modified to make a circularly linked list
public boolean add(E e) {
LinkEntry<E> ne = new LinkEntry<E>();
ne.element = e;
if (head == null && tail == null) {
head = tail = ne;
head.next = head;
tail.next = head;
} else {
tail.next = ne;
tail = ne;
tail.next = head;
}
return true;
}
