use warnings;
use strict;

my @arr = (29,24,0,24,24,12,0,0,10,10,10,19,17,15,13,1,12,12,24);

sub print_uniques
{
   my $array_ref = shift;
   
   my @sorted = sort {$a<=>$b} @$array_ref;
   my $last_printed = undef;
   
   foreach my $element (@sorted)
   {
       if (not defined $last_printed) # special case for 1st number
       {
          print "$element ";
          $last_printed = $element;
          next;
       }
       
       # do not print duplicates of the previously printed number
       
       print "$element " unless $element == $last_printed;
       $last_printed = $element;       
   }
   
   print "\n";
}

print_uniques(\@arr); #0 1 10 12 13 15 17 19 24 29