/**
 * 回溯算法
 *
 * 约瑟芬杀人问题
 * */
public class Josephus {
    private static int N = 20;
    private static int M = 5;   //数到M就咔嚓一个人

    class Node{
        int val;    //下标
        Node next;
        public Node(int val){
            this.val = val;
        }
    }

    public void killNode(){
        Node header = new Node(1);    //第一个结点
        Node x = header;    //目前被点到的人

        for(int i = 2;i <= N;i++){
            x = (x.next = new Node(i));
        }

        x.next = header; //头尾相接

        System.out.println("被咔擦的顺序为:");

        while(x != x.next){
            //至少还有两人 仍然继续报数，咔擦
            for(int i = 1;i < M;i++){
                x = x.next;
            }
            System.out.println(x.next.val + "被咔擦了");
            x.next = x.next.next;
        }
        System.out.println("最后的幸运儿是：" + x.val);
    }

    public static void main(String[] args){
        Josephus j = new Josephus();
        j.killNode();
    }
}