use Data::Dumper;

my %counts;
my @array = qw (aa bb cc aa aa cc cc dd aa aa);
%counts = map {$_ => ++$counts{$_} } @array;
print Dumper(\%counts);

##</code><code>##

my %counts = map {
    my $n;
    do { $n = (($last=$_) ... ($last ne $_)) } while $n =~ /E0$/;
    ($last => $n);
} sort @array;