use File::Find;
find (\&wanted_user, "$dir");

sub wanted_user
{
        %sum = ();
        next unless (-d $_);
        ($user,$size) = (stat($_))[4,7] or die "can't stat: $!\n";
        push ( @{$sum{$user}}, $size );
}


foreach $user (sort keys %sum) {
        print "$user: @{$sum{$user}}\n";
}