bench.pl

#!/usr/bin/env perl
use strict;
use warnings;
use 5.010;
use List::MoreUtils qw(uniq);
#use Data::Dumper::Names;
use Benchmark qw(:all) ;

sub test1 {
  my @tab = (["12","25","2","18","9","25","18","30","30","12","30","30","18","12"],["154","12","56","8","22","88","74","12","56","32","88","88","56","12","12","56"]);

  foreach my $row (@tab) {
    @$row = uniq @$row;
  }
}

sub test2 {
  my @tab = (["12","25","2","18","9","25","18","30","30","12","30","30","18","12"],["154","12","56","8","22","88","74","12","56","32","88","88","56","12","12","56"]);

  for(my $i=0;$i<=$#tab;$i++)
  {
    my $ref=$tab[$i];
    my %values= map {$_ => 1 } @$ref;
    $tab[$i]=[keys(%values)];
  }

}

timethese(1000000, {'test1' => \&test1, 'test2' =>  \&test2} );