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);
    }
}