sub test_ordered
{
    #test if two arrays are ordered in same way
    #assuming no duplicate and left array is always 
    #be greater/superset or equal to the right one

    #    L    R
    my ($ar1,$ar2)= @_;

    my %h;

    @h{@$ar1} = (0..$#{$ar1});

    my $last = -1;
    foreach (@h{@$ar2}) {
       return 0 unless $_ >= $last;
       $last = $_;
    }

    return 1;
}