sub c {
    my $d = shift;
    $d->{$_} = $_ foreach (0 .. 200);
}

##</code><code>##

b: 154 wallclock secs (153.27 usr + 0.00 sys = 153.27 CPU) @ 1216.55/s (n=100000)
c: 152 wallclock secs (153.17 usr + 0.00 sys = 153.17 CPU) @ 1216.55/s (n=100000)
f: 156 wallclock secs (156.57 usr + 0.00 sys = 156.57 CPU) @ 1252.98/s (n=100000)