use strict; use warnings;
use Data::Dumper;

my @a = ( 2,2,2,3,3,4,4 );

my (%hash, %count);
my $prev;

foreach ( 0..$#a ) {
	my $cur = $a[$_]; warn "cur:$cur\n";

	if ( ($prev && $cur != $prev || $_ == $#a) ) {

		my ($prev_key) = keys %count; 

		if ( !$prev_key ||( $count{$prev_key} ) <= $hash{$prev} ) {
			delete $count{$prev_key} if $prev_key;
			$count{$prev} = $hash{$prev};
		}
	}
	$hash{$cur}++;
	$prev = $cur;
}

warn Dumper \%count;

##</code><code>##

$VAR1 = {
          '2' => 3
        };