use strict;
use warnings;

my $max=0;
my %val=map { $_ => $max++ } split //,'MDCLXVI';


sub rtol {
    my ($word)=@_;

    my @r = (".") x $max;
    my $last = $max + 1;

    while (length $word) {
        my $c=chop $word;
        if ($val{$c}<$last) {
            $r[$val{$c}]=$c;
            $last=$val{$c};
        }
    }
    return join "",@r;
}

sub ltor {
    my ($word)=@_;

    my @r = (".") x $max;
    my $last = -1;

    for my $c (split //,$word) {
        if ($val{$c}>$last) {
            $r[$val{$c}]=$c;
            $last=$val{$c};
        }
    }
    return join "",@r;
}

printf "%7s => %7s  ( %7s : %-3s) ( %7s : %-3s )\n", qw(Input Expect LtoR ok? RroL ok?);
printf "%7s    %7s    %7s   %-3s    %7s   %-3s  \n", ("---") x 6;
while(<DATA>) {
    last unless /\S/;
    chomp;
    my ($input,$expect)=split /\s+/,$_;
    my $ltor=ltor($input);
    my $rtol=rtol($input);

    printf "%7s => %7s  ( %7s : %-3s) ( %7s : %-3s )\n",
        $input, $expect,
        $ltor, $ltor eq $expect ? 'Ok' : 'Not',
        $rtol, $rtol eq $expect ? 'Ok' : 'Not';

}


__END__
I              ......I
IV             .....V.
V              .....V.
VI             .....VI
IX             ....X..
X              ....X..
XI             ....X.I
XIV            ....XV.
XV             ....XV.
XVI            ....XVI
XIX            ....X.I
X              ....X..
XL             ....X..
LX             ...LX..
XC             ....X..
CLXIX          ..CLX.I
CDXLVI         .D..XVI
MCMXCVI        M.C.XVI
MDCLI          MDCL..I

##</code><code>##

  Input =>  Expect  (    LtoR : ok?) (    RroL : ok? )
    ---        ---        ---   ---        ---   ---  
      I => ......I  ( ......I : Ok ) ( ......I : Ok  )
     IV => .....V.  ( ......I : Not) ( .....V. : Ok  )
      V => .....V.  ( .....V. : Ok ) ( .....V. : Ok  )
     VI => .....VI  ( .....VI : Ok ) ( .....VI : Ok  )
     IX => ....X..  ( ......I : Not) ( ....X.. : Ok  )
      X => ....X..  ( ....X.. : Ok ) ( ....X.. : Ok  )
     XI => ....X.I  ( ....X.I : Ok ) ( ....X.I : Ok  )
    XIV => ....XV.  ( ....X.I : Not) ( ....XV. : Ok  )
     XV => ....XV.  ( ....XV. : Ok ) ( ....XV. : Ok  )
    XVI => ....XVI  ( ....XVI : Ok ) ( ....XVI : Ok  )
    XIX => ....X.I  ( ....X.I : Ok ) ( ....X.. : Not )
      X => ....X..  ( ....X.. : Ok ) ( ....X.. : Ok  )
     XL => ....X..  ( ....X.. : Ok ) ( ...L... : Not )
     LX => ...LX..  ( ...LX.. : Ok ) ( ...LX.. : Ok  )
     XC => ....X..  ( ....X.. : Ok ) ( ..C.... : Not )
  CLXIX => ..CLX.I  ( ..CLX.I : Ok ) ( ..CLX.. : Not )
 CDXLVI => .D..XVI  ( ..C.XVI : Not) ( .D.L.VI : Not )
MCMXCVI => M.C.XVI  ( M.C.XVI : Ok ) ( M.C..VI : Not )
  MDCLI => MDCL..I  ( MDCL..I : Ok ) ( MDCL..I : Ok  )