编写deque类的实现

Question

我目前正在使用ListNodes定义我自己的类Deque，名为myDeque。我面临的问题涉及到remove()方法。你如何修改Deque指向后面的节点并删除曾经是“后退”的内容？谢谢

private ListNode<E> front; // Reference to first ListNode in the Deque 
private ListNode<E> back; // Reference to last ListNode in the Deque 
private int numElems;  // Current number of ListNodes in the Deque 

public MyDeque() { 
    front = null; 
    back = null; 
    numElems = 0; 
} 

public void addLast(E e) { 
if (numElems == 0){ 
front = new ListNode<E>(e,null); 
back = front; 
} else { 
back.next = new ListNode<E>(e,null);  
back = back.next; 
} 
numElems += 1; 
} 

public boolean add(E e) { 
if (numElems == 0){ 
front = new ListNode<E>(e,null); 
back = front; 
} else { 
ListNode<E> prevData = back; 
back.next = new ListNode<E>(e,null);  
back = back.next; 
} 
numElems += 1; 
return true; 
} 

public boolean remove(Object o) { 
    if (numElems == 0){ 
    throw new NoSuchElementException(); 
    } 
    return false; 
} 

public E removeLast() { 
if (numElems == 0){ 
throw new NoSuchElementException(); 
} 
else{ 
numElems = numElems - 1; 
} 
return null; 
} 

Answer 1

back = back.back; //modify the Deque to point to the node behind back 
back.next = null; //and delete what used to be "back"