1. [代码]首先是借口定义

* @author xzf

public interface MyDeque<E> {

* insert the specified element at the front of this deque if it is possible

* to do so immediately without violating capacity restrictions.

@param e the element to add

void addFirst(E e);

* insert the specified element at the end of this deque if it is possible

* to do so immediately without violating capacity restrictions.

* @param e the element to add

void addLast(E e);

* @return the head of this deque

E removeFirst();

* @return the tail of this deque

E removeLast();

* insert the specified element into the queue represented by this deque

* (in other words, at the tail of this deque) if it is possible

* to do so immediately without violating capacity restrictions.

* @return true upon success

boolean add(E e);

* retrieve and remove the head of this queue represented by this deque

* (in other words, the first element of this deque).

* @return the head of the queue represented by this deque

* push an element onto the stack represented by this deque

* (in other words, at the head of this deque) if it is possible

to do so immediately without violating capacity restrictions.

* @param e the element to push

void push(E e);

* pop an element from the stack represented by this deque. In other words,

* removes and returns the first element of this deque.

* @return the element at the front of this deque

* return the number of elements of this dceque.

* @return the number of elements of this dceque

2. [代码]自定义LinkedList实现类

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* @author xzf

* @param <E>

public class MyLinkedList<E> implements MyDeque<E>{

private Entry<E> header;

private int size;

public MyLinkedList()

header = new Entry<E>(null, null, null);

size = 0;

header.next = header.privious = header;

* insert the specified element at the front of this deque if it is possible

* to do so immediately without violating capacity restrictions.

* @param e the element to add

public void addFirst(E e) {

addBefore(e, header.next);

* insert the specified element at the end of this deque if it is possible

* to do so immediately without violating capacity restrictions.

@param e the element to add

public void addLast(E e) {

addBefore(e, header);

* retrieve and remove the first element of this deque.

* @return the head of this deque

public E removeFirst() {

return remove(header.next);

* @return the tail of this deque

public E removeLast() {

return remove(header.privious);

* insert the specified element into the queue represented by this deque

* (in other words, at the tail of this deque) if it is possible

* to do so immediately without violating capacity restrictions.

* @return true upon success

public boolean add(E e) {

addBefore(e, header);http://www.huiyi8.com/jiaoben/ 

* retrieve and remove the head of this queue represented by this deque

* (in other words, the first element of this deque).

* @return the head of the queue represented by this deque

public E remove() {

return removeFirst();

* push an element onto the stack represented by this deque

* (in other words, at the head of this deque) if it is possible

* to do so immediately without violating capacity restrictions.

* @param e the element to push