qw/a a b c d d a/

##</code><code>##

user wants?
(a => 2, b => 1, c => 1, d => 2, a => 1):
# or
(a => 3, b => 1, c => 1, d => 2);

##</code><code>##

my %saw;
my @sum=map {$_ => $saw{$_}} grep !$saw{$_}++, @array;