public void addFirst(int data) {
if (size == capacity) this.remove(tail.data);
DLLNode temp = new DLLNode(data);
temp.next = head;
if (head != null) head.prev = temp;
else tail = temp;
head = temp;
size++;
hash.put(data, temp);
}
public int remove(int data) {
DLLNode trv = hash.get(data);
if (trv == null || size <= 0) return -1;
if (trv == tail) {
tail = tail.prev;
tail.next = null;
trv.prev = null;
} else if (trv == head) {
head = head.next;
head.prev = null;
trv.next = null;
} else {
trv.prev.next = trv.next;
trv.next.prev = trv.prev;
trv.next = null;
trv.prev = null;
}
hash.put(trv.data, null);
size--;
return trv.data;
}