void Isloop(Llink head)
{if(!head||!head->next)return;Llink p,q;bool loop=false;p=q=head->next;while(q&&q->next)//判断是否有环
 {p=p->next;q=q->next->next;if(p==q){loop=true;break;}}if(!loop)cout<<"This link has not loop\n";else{cout<<"This link has a loop\n";Llink r=p;q=head->next;int nonloop=1,loopcount=1;//nonloop计算非环结点数，loopcount计算环上结点数do//计算环上的结点数
  {p=p->next;++loopcount;}while(p!=r);--loopcount;while(p!=q)//得到环的入口结点，同时计算得到非环的结点数
  {p=p->next;q=q->next;++nonloop;}--nonloop;cout<<"\nStart of loop: "<<p->data<<endl;  cout<<"\nCount of nonloop: "<<nonloop<<"\nCount of loop: "<<loopcount<<"\nCount of Linknode: "<<nonloop+loopcount<<endl;}
}

bool IsExitsLoop(slist *head)
{  slist *slow = head, *fast = head;  while ( fast && fast->next )   {  slow = slow->next;  fast = fast->next->next;  if ( slow == fast ) break;  }    return !(fast == NULL || fast->next == NULL);
}  

slist* FindLoopPort(slist *head)
{  slist *slow = head, *fast = head;    while ( fast && fast->next )   {  slow = slow->next;  fast = fast->next->next;  if ( slow == fast ) break;  }    if (fast == NULL || fast->next == NULL)  return NULL;  slow = head;  while (slow != fast)  {  slow = slow->next;  fast = fast->next;  }  return slow;
} 

 bool isloop(Llink p)
{if(!p||!p->next)return true;int a[MAXSIZE],n=0;memset(a,0,sizeof(int)*MAXSIZE);p=p->next;while(p){if(a[p->data]==-1)//存在环时，会发生冲突
  {cout<<"\nLoop node: "<<p->data<<endl<<"\nLen of node: "<<n<<endl;return true;}a[p->data]=-1;++n;p=p->next;}return false;
}
Llink CreatlinkLoop()

 bool isloop(Llink p)
{if(!p||!p->next)return true;int a[MAXSIZE],n=0;memset(a,0,sizeof(int)*MAXSIZE);p=p->next;while(p){if(a[p->data]==-1)//存在环时，会发生冲突
  {cout<<"\nLoop node: "<<p->data<<endl<<"\nLen of node: "<<n<<endl;return true;}a[p->data]=-1;++n;p=p->next;}return false;
}
Llink CreatlinkLoop()