sub all{
    my @seq1 = split / +/, $_[0];
    my @seq2 = split / +/, $_[1];
    my $idx  = LCSidx( \@seq1, \@seq2 );
    my @result = ('  ') x @seq1;
    @result[@$idx] = @seq1[@$idx];
    return split / {2,}/, join ' ', @result; #in order seen
       #or
    return sort {length $b <=> length $a} split / {2,}/, join ' ', @result; #sorted by length
}