sub maximize_rows {
  my @array = @_;

  my %hash = ();
  foreach (@array) {
    $hash{$_->[0]}++;
    $hash{$_->[1]}++;
  }

  # the following is done to generate a fitness for each   
  # pair..which happens to be the better fitness of the 
  # elements within the pair
  push @$_, ($hash{$_->[0]} < $hash{$_->[1]} ? $hash{$_->[1]}:$hash{$_->[0]}) foreach (@array);
  
  # sort by fitness
  @array = sort { $b->[2] <=> $a->[2] } @array;
  
  my $counter = 0;
  foreach my $x (0..$#array - 1) {
    next unless $array[$x];
    foreach my $y ($x+1..$#array) {
      next unless $array[$y];
      %hash = ();
      $hash{$_}++ foreach (@{$array[$x]}[0,1],@{$array[$y]}[0,1]);
      if (scalar keys %hash == 4) {
        $counter++;
        print "$counter = $array[$x]->[0] $array[$x]->[1]  $array[$y]->[0] $array[$y]->[1]$/";
        $array[$x] = $array[$y] = undef;
        last;
      }
    }
  }
  @array = grep { $_ } @array;
  print "Unused ",$_ + 1,": $array[$_]->[0] $array[$_]->[1]$/" foreach (0..$#array);
}

__DATA__
7 7 1 1 1 2 2 2 2 5 5 5 5 4 4 4 4 4 3 3 3 3 3 8 8 8 8 8 8 6 6 6 6 6 6 6
====================
1 = 1 2
2 = 1 3
3 = 1 4
4 = 2 3
5 = 2 4
6 = 2 5
7 = 3 4
8 = 3 5
9 = 3 6
10 = 4 5
11 = 4 6
12 = 5 6
13 = 6 7
14 = 6 8
15 = 7 8
15 counts
$VAR1 = {
          '6' => 2,
          '8' => 4,
          '4' => 0,
          '1' => 0,
          '3' => 0,
          '7' => 0,
          '2' => 0,
          '5' => 0
        };
1 = 6 8
2 = 4 6
3 = 3 6
4 = 2 6
5 = 5 6
6 = 1 6
7 = 6 7
8 = 4 8
9 = 3 8
10 = 2 8
11 = 5 8
12 = 1 8
13 = 3 4
14 = 2 4
15 = 4 5
16 = 2 3
17 = 3 5
18 = 1 7
18 counts
$VAR1 = {
          '6' => 0,
          '8' => 0,
          '4' => 0,
          '1' => 0,
          '3' => 0,
          '7' => 0,
          '2' => 0,
          '5' => 0
        };
1 = 1 3  2 4
2 = 1 4  2 3
3 = 3 4  5 6
4 = 3 5  4 6
5 = 3 6  4 5
6 = 6 7  1 2
7 = 6 8  2 5
Unused 1: 7 8
next
1 = 6 8  3 4
2 = 4 6  3 8
3 = 3 6  4 8
4 = 2 6  5 8
5 = 5 6  2 8
6 = 1 6  2 4
7 = 6 7  1 8
8 = 4 5  2 3
9 = 3 5  1 7