循环链表的经典实现（JAVA）
public class LinkedListNode {//链表节点 public LinkedListNode previous;//前一节点 public LinkedListNode next;//后一节点 public Object object;//节点中存的值 public long timestamp; public LinkedListNode(Object object, LinkedListNode next, LinkedListNode previous) { this.object = object; this.next = next; this.previous = previous; } public void remove() {//删除自己 previous.next = next; next.previous = previous; } public String toString() { return object.toString(); }}import java.util.*;public class LinkedList {//循环链表 //头指针，哑的，第一个节点的前面，最后一个节点的后面 private LinkedListNode head = new LinkedListNode("head", null, null); public LinkedList() { head.next = head.previous = head; } public LinkedListNode getFirst() {//获取循环链表的第一个节点 LinkedListNode node = head.next; if (node == head) { return null; } return node; } public LinkedListNode getLast() {//获取循环链表的最后一个节点 LinkedListNode node = head.previous; if (node == head) { return null; } return node; } public LinkedListNode addFirst(LinkedListNode node) {//将节点插入到链表的第一个位置,头节点之后. node.next = head.next; node.previous = head; node.previous.next = node; node.next.previous = node; return node; } public LinkedListNode addFirst(Object object) {//将值插入到链表的第一个位置,头节点之后. LinkedListNode node = new LinkedListNode(object, head.next, head); node.previous.next = node; node.next.previous = node; return node; } public LinkedListNode addLast(Object object) {//将值插入到链表的最后一个位置,头节点之前 LinkedListNode node = new LinkedListNode(object, head, head.previous); node.previous.next = node; node.next.previous = node; return node; } public void clear() {//清空循环链表 //Remove all references in the list. LinkedListNode node = getLast(); while (node != null) { node.remove(); node = getLast(); } //Re-initialize. head.next = head.previous = head; } public String toString() { LinkedListNode node = head.next; StringBuffer buf = new StringBuffer(); while (node != head) { buf.append(node.toString()).append(", "); node = node.next; } return buf.toString(); }}