【C语言】判断单链表是否带环

思想：快慢指针，若为环，则快指针一定能追上慢指针

intIsCycle(Plinklist*pplist)

{

          assert(pplist);

          Node*fast = *pplist;

          Node*slow = *pplist;

          while(fast&&fast->next)

          {

                   fast = fast->next->next;

                   slow = slow->next;

                   if(fast == slow)

                   {

                             return1;

                   }

          }

          return0;

}