约瑟夫环问题：一圈共有N个人，开始报数，报到M的人自杀，然后重新开始报数，问最后自杀的人是谁？

//链表实现
public class Node{
    public int value;
    public Node next;
    
    public Node(int data){
        this.value=data;
    }
}
public Node josephuskill(Node head,int m){
    if(head==null||head.next==head||m<1){
        return head;
    }
    Node last=head;
    while(last.next!=head){
        last=last.next;
    }
    int count=0;
    while(head!=last){
        if(++count==m){
            last.next=head.next;
            count=0;
        }
        else{
            last=last.next;
        }
        head=last.next;
    }
    return head;
}