数据结构之循环链表

package com.dby.link;/** * Created by suzunshou on 2016/4/11. * 链表的元素不能随机访问 * 元素前面和后面不会出现多个元素相连的情况 * 元素相互依赖，串联而成 * 链表只有一个表头 * 循环链表首尾相连,尾结点指向首结点 */public class LinkedList {    //结点类    private class Node {        //数据        private Object data;        //下一个结点的地址        private Node next = null;        public Node(Object data) {            this.data = data;        }    }    private Node first = null;    private Node last = null;    private int size;    //循环链表，头尾相连，插入结点到某个位置    public void insert(Object data, int index) {        //新结点        Node newNode = new Node(data);        //空链表        if (first == null) {            first = newNode;            first.next = first;            return;        }        //只有一个结点        if (index - 1 == 0) {            newNode.next = first.next;            first.next = newNode;            return;        }        //普通情况        Node curr = first.next;        int count = 0;        //遍历直到起始位置        while (curr != first && count < index - 2) {            curr = curr.next;            count++;        }        //插入结点，把前一个结点和后一个结点断开，两端接上新结点        if (count == index - 2) {            newNode.next = curr.next;            curr.next = newNode;        }        if (newNode == first.next) {            first = newNode;        }         size++;    }    //输出约瑟夫环被删除的元素，报数m    public void output_josephus(int m) {        //首结点        Node curr = first;        //遍历返回到起始点        while (curr.next != curr) {            //找到m索引处的结点            for (int i = 1; i < m; i++) {                curr = curr.next;            }            //找到被删除的结点            Node del = curr.next;            //输出结点值            System.out.println(del.data);            //断开被删除结点，连接被删结点的下一个结点            curr.next = curr.next.next;            //删除结点            del = null;        }        //输出并删除最后一个结点        System.out.println(curr.data);        curr = null;    }    public static void main(String[] args) {        LinkedList ll = new LinkedList();        for (int i = 1; i < 8; i++) {            ll.insert2(i, i);        }        ll.output_josephus(2);    }}