my @z;
for (my $r = 0; $r <= 2; $r++)
{$z[$r]=$subgraphs[0][$r];}

for my $QT (@z ){
    print Dumper $QT;
    for my $triplet ( @S ){
        my %Pie;
        undef @Pie{@$QT};
        delete @Pie{ @$triplet };
        print "@$triplet\n" if keys(%Pie) <= ( @$QT - @$triplet ) ;
    }
}