两个有序单向链表的合并

void And(linkP A, linkP B){    linkP p = A->next;    linkP q = B->next;    free(B);// 释放头指针；    linkP r = A;    while(p && q)    {        if (p->data <= q->data)        {            r->next = p;            r = p;            p = p->next;        }        else        {            r->next = q;            r = q;            q = q->next;        }    }    if (p == NULL) p = q;    r->next = p;}