站在Java的角度看LinkedList

站在Java的角度看，玩队列不就是玩对象引用对象嘛！

public class LinkedList<E> implements List<E>, Deque<E> {
  Node<E> first;
  Node<E> last;
  int size;

  public boolean add(E e) {
        final Node<E> l = last;
        final Node<E> newNode = new Node<>(l, e, null);
        last = newNode;
        if (l == null)
            first = newNode;
        else
            l.next = newNode;
        size++;
        modCount++;
        return true;
    }

  private static class Node<E> {
        E item;
        Node<E> next;
        Node<E> prev;

        Node(Node<E> prev, E element, Node<E> next) {
            this.item = element;
            this.next = next;
            this.prev = prev;
        }
    } 
}

 单链表反转：

/**  
     * 递归，在反转当前节点之前先反转后续节点  
     */  
    public static Node reverse(Node head) {  
        if (null == head || null == head.getNextNode()) {  
            return head;  
        }  
        Node reversedHead = reverse(head.getNextNode());  
        head.getNextNode().setNextNode(head);  
        head.setNextNode(null);  
        return reversedHead;  
    }  
  
    /**  
     * 遍历，将当前节点的下一个节点缓存后更改当前节点指针  
     *   
     */  
    public static Node reverse2(Node head) {  
        if (null == head) {  
            return head;  
        }  
        Node pre = head;  
        Node cur = head.getNextNode();  
        Node next;  
        while (null != cur) {  
            next = cur.getNextNode();  
            cur.setNextNode(pre);  
            pre = cur;  
            cur = next;  
        }  
        //将原链表的头节点的下一个节点置为null，再将反转后的头节点赋给head     
        head.setNextNode(null);  
        head = pre;  
          
        return head;  
    }

 对于数组问题，一般我们要新建数组，必要时移动下标