Is it right answer?

Spoilered answer

create table xt1(n1 number,v1 varchar2(1));
create index xt_i1 on xt1(n1,v1);
alter table xt1 add constraint uq_xt1 unique (n1,v1) using index xt_i1;

create table xt2(a number unique);
create bitmap index xt_i2 
  on xt1(n1,v1)
  from xt1,xt2
  where xt1.n1=xt2.a;

col column_name format a30;

select index_name,column_name 
from user_ind_columns 
where table_name='XT1' 
order by index_name,column_position;