sub get_pairs {
  my %hash = ();
  $hash{$_}++ foreach @_;
  my @keys = sort { $hash{$b} <=> $hash{$a} } keys %hash;
  my $counter = 0;
  
  foreach my $x (0..$#keys - 1) {
    next unless $hash{$keys[$x]};
    foreach my $y ($x+1..$#keys) {
      last unless $hash{$keys[$x]};
      next unless $hash{$keys[$y]};
      $counter++;
      print "$counter = ",($keys[$x] < $keys[$y] ? "$keys[$x] $keys[$y]":"$keys[$y] $keys[$x]"),$/;
      $hash{$keys[$x]}--;
      $hash{$keys[$y]}--;
    }
  }
  print "$counter counts$/"  print "$counter counts$/"
  print Dumper(\%hash); #to see how many matches are made
}

get_pairs(@array);

__DATA__
1 = 3 6
2 = 4 6
3 = 1 6
4 = 6 7
5 = 5 6
6 = 6 8
7 = 2 6
8 = 3 4
9 = 1 3
10 = 3 7
11 = 3 5
12 = 3 8
13 = 1 4
14 = 4 7
15 = 4 5
16 = 4 8
17 = 1 7
17 counts
$VAR1 = {
          '6' => 0,
          '8' => 0,
          '4' => 0,
          '1' => 0,
          '3' => 1,
          '7' => 0,
          '2' => 0,
          '5' => 1
        };