一个带头结点的单链表拆分成两个带头结点的单链表L1和L2

void split(LinkNode *&L,LinkNode *&L1,LinkNode *&L2)
{    LinkNode * p=L->next,* q,* r1;
     L1=L;            
     r1=L1;            //r1始终指向L1的尾结点
     L2=(LinkNode *)malloc(sizeof(LinkNode);
     L2->next=NULL;
     while(p!=NULL)
     {    r1->next=p;
          r1=p;
          p=p->next;
          q=p->next;
          p->next=L2->next;
          L2->next=p;
          p=q;
     }
     r1->next=NULL;
}