You can do quite a lot better with a properly Perlish version. 
my $ans = 0;
my $total = 0;
my $bit;

for my $num (0 .. 16777215) {
    $bit = 1;
    $total += $_ ? $bit++ : -$bit++
            for unpack("b24", pack "L", $num) =~ /./g;
    $ans++ unless $total;
    $total = 0;
}

print "$ans\n";

[download]
$ make t
cc     t.c   -o t
$ time ./t
187692

real    0m3.992s
user    0m3.990s
sys     0m0.000s
$ time perl t.pl 
187692

real    6m54.313s
user    6m53.290s
sys     0m0.510s
Still, obviously, you're never going to get anywhere near the same ballpark as C with Perl code in things as machine-friendly as this.

Makeshifts last the longest.

In reply to Re: Believably slow.. by Aristotle
in thread Unbelievably slow.. by kiat

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