#my @chars = grep !$seen{$_}++, $text =~ /./g;
my @chars = 'a'..'z';

my ($re) = map qr/$_/,
           join '|',
           map "(?<=${_}{3})$_+",
           map quotemeta,
           @chars;

$text =~ s/$re//g;

##</code><code>##

#my @chars = grep !$seen{$_}++, $text =~ /./g;
my @chars = 'a'..'z';

my ($re) = map qr/$_/,
           join '|',
           map "${_}{4,}",
           map quotemeta,
           @chars;

$text =~ s/($re)/substr($1,0,3)/eg;

##</code><code>##

#my @chars = grep !$seen{$_}++, $text =~ /./g;
my @chars = 'a'..'z';

my ($re) = map qr/$_/,
           join '|',
           map "${_}{4,}",
           map quotemeta,
           @chars;

$text =~ s/$re/substr($text,$-[0],3)/eg;