p->next->prev = p->next; p->prev->next = p->prev; delete p;

p->prev->next = p->next; p->next->prev = p->prev; delete p;

p->next->prev = p->prev; p->next->prev->next = p->next; delete p;

p->prev->next = p->next; p->prev->next->prev = p->prev; delete p;