找出递增有序的单链表A和B的公共结点并存放于A中

其余结点全部释放

LinkList Union(LinkList &A,LinkList B)
{pa=A->next;pb=B->next;pc=A;while(pa&&pb){if(pa->data==pb->data){pc->next=pa;pc=pa;pa=pa-next;s=pb;pb=pb->next;free(s);}else if(pa->data<pb->data){s=pa;pa=pa->next;free(s);}else{s=pb;pb=pb->next;free(s);}}while(pa){s=pa;pa=pa->next;free(s);}while(pb){s=pb;pb=pb->next;free(s);}pc->next=NULL;free(B);return A;
}