my @chars = split //, $string;
my $h = ();
$h{$_}++ foreach @chars;
print "True" if $h{k} >= 2 || $h{r} == 2 && $h{w} == 2 || $h{k} == 1 && $h{r} == 1 && $h{w} == 2;

for ($string) {
   print "yes" if tr/k// >= 2 and tr/r// >= 2 and tr/w// >= 2;
}

use strict;
use warnings;
use Benchmark;

my @strings;

my @chars = 'a'..'z';

for (1..10) {
    my $len = int ( rand(100)) + 10;

    my $string;
    for(1 .. $len) {
       $string .= $chars[int ( rand(@chars) )];
    }

    push @strings, $string;
}

print scalar @strings, " strings created !\n";

my $iterations = 10000;
my $count = 0;

timethese(
    $iterations,
    {
        "esskar" => sub {
            foreach (@strings) {
               my @chars = split //, $_;
               my %h = ();
               $h{$_}++ foreach @chars;

               $count += is_true($h{k}, $h{r}, $h{w});
            }
        }
    }
);

print "esskar: $count\n";

$count = 0;
timethese(
    $iterations,
    {
        "pq" => sub {
            foreach (@strings) {
                $count += is_true( tr/k//, tr/r//, tr/w// );
            }
        }
    }
);

print "pq: $count\n";

sub is_true {
   my ($k, $r, $w) = @_;

   $k ||= 0;
   $r ||= 0;
   $w ||= 0;

   return $k >= 2 || $r == 2 && $w == 2 || $k == 1 && $r == 1 && $w == 2;
}
^Z
10 strings created !
Benchmark: timing 10000 iterations of esskar...
    esskar: 15 wallclock secs (14.47 usr +  0.00 sys = 14.47 CPU) @ 691.13/s (n=10000)
esskar: 60000
Benchmark: timing 10000 iterations of pq...
        pq:  0 wallclock secs ( 0.34 usr +  0.00 sys =  0.34 CPU) @ 29069.77/s (n=10000)
            (warning: too few iterations for a reliable count)
pq: 60000