# This is pseudo code
for each $record (@records)
{
  push $record into the right $bin;
  $records++;
}
$key = 1;
while ($records--)
{
  ++$key while(empty $bin{$key});
  pop $record from $bin{$key} and print it;
}
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That's at least the way I understood what you want to do. If there's actually a sorting criteria for the output (other than "0 2 4 8 ...", this would have to be different. Unless I missed something, the problem is there's no way to tell that "1 0" comes before "2 0" or after "3 256", that is, your description is too loose.