rem: if(p->id == key->id) return 0; else return 1;
add: if (p->id == key->id) return 0;  return 1;
context: team_struct_compare(void *_p, const void *_key){	struct team *p = _p;	const struct team_key *key = _key;	if(p->id == key->id) return 0;	else return 1;}