单向链表实现约瑟夫环

public class PersonNode 
{
    public int Id { get; set; }

    public PersonNode(int id) 
    {
        Id = id;
    }

    public PersonNode NextPerson { get; set; }
}

/// <summary>
/// 创建一个环形的单向链表
/// </summary>
public class MyJoseph
{
    //创建一个头节点，不包含任何意义的数据
    private PersonNode first = new PersonNode(-1);

    /// <summary>
    /// 添加节点
    /// </summary>
    /// <param name="num">需要创建几个节点</param>
    public void addPerson(int num)
    {
        if (num <= 0) 
        {
            Console.WriteLine("num的值不正确");
            return;
        }

        //辅助指针帮助构建环形链表
        PersonNode currentNode = null;

        //使用for循环创建我们的环形链表
        for (int i = 1; i <= num; i++)
        {
            //根据编号创建节点
            PersonNode person = new PersonNode(i);

            //如果是第一个节点
            if (i==1)
            {
                first = person;
                first.NextPerson = first; //构成环形
                currentNode = first;//让currentNode指向第一个节点，因为fist节点不能动
            }
            else
            {
                //让当前节点指向新增加的节点
                currentNode.NextPerson = person;
                //将新增的节点指向第一个节点完成闭环
                person.NextPerson = first;
                //改变当前节点的位置
                currentNode = person;
            }
        }
    }

    public void Print() 
    {
        if (first == null)
        {
            Console.WriteLine("链表为空");
            return;
        }

        PersonNode currentNode = first;
        while (true)
        {
            Console.WriteLine($"编号{ currentNode.Id }");
            if (currentNode.NextPerson == first) break;
            currentNode = currentNode.NextPerson;
        }
    }

    /// <summary>
    /// 踢出圈
    /// </summary>
    /// <param name="startId">从第几个人开始踢</param>
    /// <param name="num">数几次</param>
    /// <param name="personNum">圈内总人数</param>
    public void Kill(int startId,int num,int personNum) 
    {
        if (first == null || startId < 1 || startId > personNum) {
            Console.WriteLine("参数有误");
            return;
        }

        PersonNode temp = first;

        //找到最后一个节点
        while (true)
        {
            //等式成立则代表遍历到最后
            if (temp.NextPerson == first) break;
            temp = temp.NextPerson;
        }

        //first 和 temp 向前移动一个节点
        for (int i = 0; i < startId - 1; i++)
        {
            first = first.NextPerson;
            temp = temp.NextPerson;
        }

        while (true)
        {
            if (temp == first) break;

            //从当前节点往后数，数出需要出圈的人
            for (int i = 0; i < num - 1; i++)
            {
                first = first.NextPerson;
                temp = temp.NextPerson;
            }
            Console.WriteLine($"Person出圈{ first.Id }");
            first = first.NextPerson;
            temp.NextPerson = first ;
        }
        Console.WriteLine($"最后留在圈中的Person{ first.Id }");
    }
}

//调用
MyJoseph myJoseph = new MyJoseph();
myJoseph.addPerson(5);
myJoseph.Print();
myJoseph.Kill(1,2,5);
myJoseph.Print();
Console.Read();