$hash{ sprintf "%050d", $_ } = 1 for 0 .. 2e6;;
print total_size \%hash;;
70183684

$hash{ sprintf "%012d", $_ } = 1 for 0 .. 2e6;;
print total_size \%hash;;
67660852

##</code><code>##

$a[ $_ ] = sprintf "%050d", $_ for 0 .. 2e6;;
print total_size \@a;;
30408448