public class MyLinkedList<E> {
private Node<E> head, tail;
public MyLinkedList() {
head = null;
tail = null;
}
public E getFirst() {
if (head == null) {
return null;
}
else {
return head.element;
}
}
public E getLast() {
if (head==null) {
return null;
}
else {
return tail.element;
}
}
public void prepend(E e) {
Node<E> newNode = new Node<>(e);
newNode.next = head;
head = newNode;
if (tail == null)
tail = head;
}
public void append(E item) {
Node<E> newNode = new Node<>(item);
if (head == null) {
head = tail = newNode;
}
else {
tail.next = newNode;
tail = newNode;
}
}
public E removeFirst() {
if (head == null) {
return null;
}
else {
E temp = head.element;
head = head.next;
if (head == null) {
tail = null;
}
return temp;
}
}
public boolean delete(E item)
{
Node<E> ptr = head;
Node<E> prvPtr = null;
while (ptr!= null&& ((Comparable)ptr.element).compareTo(item)!= 0)
{
prvPtr=ptr;
ptr=ptr.next;
}
if (ptr == null)
return false;
if (ptr==head)
head= head.next;
else
prvPtr.next=ptr.next;
if (ptr==tail)
tail=prvPtr;
return true;
}
public String toString() {
String result = "[";
Node<E> ptr = head;
for (ptr= head;ptr!=null; ptr=ptr.next)
{
result = result + ptr.element.toString();
if (ptr.next != null)
result = result + ",";
}
result += "]";
return result;
}
public void clear() {
head = tail = null;
}
private static class Node<E> {
E element;
Node<E> next;
public Node(E element) {
this.element = element;
next = null;
}
}
}