if object_id('tempdb..#f')> 0  drop table #f
if object_id('tempdb..#g')> 0  drop table #g
if object_id('tempdb..#h')> 0  drop table #h
if object_id('tempdb..#t')> 0  drop table #t
GO
create table #f(n int, v1 int, v2 int)
GO
insert into #f (v1, v2)
select  1 ,  2  union all
select  1 ,  3  union all
select  1 ,  7  union all
select  2 ,  3  union all
select  2 ,  10  union all
select  3 ,  4  union all
select  3 ,  5  union all
select  4 ,  5  union all
select  4 ,  6  union all
select  5 ,  8  union all
select  5 ,  10  union all
select  6 ,  7  union all
select  6 ,  8  union all
select  7 ,  9  union all
select  8 ,  9  union all
select  8 ,  10  union all
select  9 ,  10 
GO
update #f set n=(select count(*) from #f f
where (f.v1=#f.v1 and f.v2<=#f.v2) or f.v1<#f.v1)
GO
select * into #g from #f where n= 1 
delete from #f where n= 1 
select i=null, * into #h from #f where  0 = 1 
select * into #t from #f where  0 = 1 
GO
declare @i int, @j int, @n int, @s varchar( 800 )

while  0 = 0 
begin
select @n=min(n) from #f where
(v1 in (select v1 from #g union all select v2 from #g) and
v2 not in (select v1 from #g union all select v2 from #g))
or
(v2 in (select v1 from #g union all select v2 from #g) and
v1 not in (select v1 from #g union all select v2 from #g))
if @n is null break
insert into #g select * from #f where n=@n
delete from #f where n=@n
end

set @i= 1 
while  0 = 0 
begin
truncate table #t
insert into #t select * from #f where n=(select min(n) from #f)
if @@rowcount= 0  break
insert into #t select * from #g
delete from #f where n=(select min(n) from #f)
while  0 = 0 
begin
delete from #t where v1 in
(select v from (select v=v1 from #t union all select v2 from #t)z
group by v having count(*)= 1 )
or v2 in
(select v from (select v=v1 from #t union all select v2 from #t)z
group by v having count(*)= 1 )
if @@rowcount= 0  break
end
insert into #h select @i, n, v1, v2 from #t
set @i=@i+ 1 
end

set @j= 1 
while @j<=@i- 1 
begin
set @s=''
select @s=@s+'('+cast(v1 as varchar( 2 ))+' '+cast(v2 as varchar( 2 ))+')'
from #h where i=@j
print cast(@j as char( 4 ))+@s
set @j=@j+ 1 
end

 1    ( 2   3 )( 1   3 )( 1   2 )
 2    ( 4   5 )( 3   4 )( 3   5 )
 3    ( 5   10 )( 1   3 )( 2   10 )( 3   5 )( 1   2 )
 4    ( 6   7 )( 1   3 )( 1   7 )( 3   4 )( 4   6 )
 5    ( 6   8 )( 3   4 )( 3   5 )( 4   6 )( 5   8 )
 6    ( 8   9 )( 1   3 )( 1   7 )( 3   5 )( 5   8 )( 7   9 )
 7    ( 8   10 )( 1   3 )( 2   10 )( 3   5 )( 5   8 )( 1   2 )
 8    ( 9   10 )( 1   7 )( 2   10 )( 1   2 )( 7   9 )