sub lcss_brute {
    my( $r1, $r2, $min ) = @_;
    my( $l1, $l2, $swap ) = ( length $$r1, length $$r2, 0 );
    ( $r1, $r2, $l1, $l2, $swap ) = ( $r2, $r1, $l2, $l1, 1 ) if $l1 > $l2;

    my( $best, @solns ) = 0;
    for my $start ( 0 .. $l2 - 1 ) {
        for my $l ( reverse 1 .. $l1 - $start ) {
            my $substr = substr( $$r1, $start, $l );
            my $o = 0;
            while( $o = 1+index( $$r2, $substr, $o ) ) {
                if( $l > $best ) {
                    $best = length $substr;
                    @solns = [ $substr, $start, $o-1 ];
                }
                elsif( $l == $best ) {
                    push @solns, [ $substr, $start, $o-1 ];
                }
            }
        }
    }
    return \@solns;
}