迅雷2014校招笔试编程题--求单链表的差集

/*已知集合A和B的元素分别用不含头结点的单链表存储，函数difference()用于求解集合A与B的差集，并将结果保存在集合A的单链表中。例如，若集合A={5,10,20,15,25,30}，集合B={5,15,35,25}，完成计算后A={10,20,30}。*/void Difference(ListNode **lista,ListNode *listb){ListNode *pa, *pb, *pre,*tmp;pa = *lista;pre = NULL;//用于实现与pa的链接，前驱节点while (pa){pb = listb;while (pb && pb->val!=pa->val){pb = pb->next;}if (pb){if (!pre){*lista = pa->next;}else{pre->next = pa->next;}tmp = pa;pa = pa->next;free(tmp);}else{pre = pa;pa = pa->next;}}}