my ($ts,$cat) = $vals[0] =~ /TS(\d+)(.+)$/;
...
  for(0..$#cats) { if ($cats[$_] =~ /$cat/) { $j = $_ } }

  for(@{$groups[0]}) { if ($ts == $_) { $i = 0 } }
  for(@{$groups[1]}) { if ($ts == $_) { $i = 1 } }
  for(@{$groups[2]}) { if ($ts == $_) { $i = 2 } }