编写双端队列类的实现

Question

我目前正在使用 ListNodes 定义我自己的名为 myDeque 的 Deque 类。我面临的一个问题涉及remove() 方法。您如何修改 Deque 以指向后面的节点并删除曾经是“后面”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"