约瑟夫链表

一、思路

二、源码

1.节点

代码如下（示例）：

package CircleSingleLinkedList;

public class Boy {
    
    
    private int no;
    private Boy Next;
    public Boy(int no){
    
    
        this.no=no;
    }
    public int getNo() {
    
    
        return no;
    }

    public void setNo(int no) {
    
    
        this.no = no;
    }

    public Boy getNext() {
    
    
        return Next;
    }

    public void setNext(Boy next) {
    
    
        Next = next;
    }
}

2.约瑟夫链表

代码如下（示例）：

package CircleSingleLinkedList;

public class CircleSingleLinkedList {
    
    
    //创建一个头结点first
    private Boy first = null;

    public void addBoy(int num) {
    
    
        if (num < 1) {
    
    
            System.out.println("输入数据无效，添加不了元素");
        }
        //创建一个临时指针cur
        Boy cur = null;
        for (int i = 1; i <= num; i++) {
    
    
            Boy boy = new Boy(i);
            if (i == 1) {
    
    
                first = boy;
                first.setNext(first); //让头节点与头节点连接起来
                cur = boy; //然新指针指向每次加进来的boy这个节点
            }
            cur.setNext(boy); // 让临时节点的下一个指向新加进来的boy
            boy.setNext(first); //新加进来的boy的下一个节点指向头部
            cur = boy; //临时节点后移
        }
    }

    //遍历整个环形链表
    public void list() {
    
    
        //如果环形链表为空，则不遍历
        if (first == null) {
    
    
            System.out.println("环形链表为空");
        }
        //需要一个临时指针来遍历
        Boy cur = first;
        while (true) {
    
    
            System.out.printf("小孩的编号为%d\n", cur.getNo());
            if (cur.getNext() == first) {
    
    
                break;
            }
            cur = cur.getNext();
        }
    }

    //小孩出圈思路
    public void getout(int num, int k, int m) {
    
    
        //验证数据
        if (first == null || k > num || k < 1) {
    
    
            System.out.println("参数输入有误。");
            return;
        }
        //创建一个辅助指针helper,事先应该让其指向环形链表的最后一个节点
        Boy helper = first;
        while (true) {
    
    
            if (helper.getNext() == first) {
    
    
                break;
            }
            helper = helper.getNext();
        }
        //报数前，先让first和helper移动 k-1 次
        for (int i = 0; i < k - 1; i++) {
    
    
            first = first.getNext();
            helper = helper.getNext();
        }
        while (first != helper) {
    
    
            //当报数时，让first和helper指针同时移动m-1次
            for (int i = 0; i < m - 1; i++) {
    
    
                first = first.getNext();
                helper = helper.getNext();
            }
            System.out.printf("出圈的人是%d\n", first.getNo());
            first = first.getNext();
            helper.setNext(first);
        }
        System.out.printf("最后留在圈中的小孩编号为%d", first.getNo());
    }
}

验证Demo

代码如下（示例）：

package CircleSingleLinkedList;

public class CircleSingleLinkedLIstDemo {
    
    
    public static void main(String[] args) {
    
    
        CircleSingleLinkedList circleSingleLinkedList = new CircleSingleLinkedList();
        circleSingleLinkedList.addBoy(5);
        circleSingleLinkedList.list();
        circleSingleLinkedList.getout(5,1,2);
    }
}

总结

思路理清楚就行了，看图说话~