@u = map { [$_, $i++] } (0,0,3,2,2);
$" = '-';
print( (map {$_->[1]} reverse sort { $a->[0] <=> $b->[0] } @u),
       "\n",
       (map {$_->[1]} sort { $b->[0] <=> $a->[0] } @u),
       "\n" );