【C语言】求带环单链表的环长

思想：快慢指针，先让快指针追上慢指针，再快指针不动，慢指针单步走，两个指针再次相遇时，慢指针在第一次相遇后所单步走的步数就为环长

           

intLengthCycle(Plinklist*pplist)

{

          assert(pplist);

          Node*fast = *pplist;

          Node*slow = *pplist;

          while(fast&&fast->next) 

          {

                   fast = fast->next->next;

                   slow = slow->next;

                   if(fast == slow)

                   {

                             break;

                   }

          }

          intcount = 0;

          do

          {

                   slow = slow->next;

                   count++;

          }while(fast != slow);

          returncount;

}