use Sort::Key 'ukeysort_inplace';
my $digits = 8;
ukeysort_inplace {
  my $a = int $_;
  length $a > $digits and die 'integer $a is too big';
  $a .= ' ' x ($digits - length $a);
  $a =~ tr/ 0123456789/0123456789a/;
  hex $a
} @array;