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

my (@array, $iIndex, $thisValue, $lastValue, @out);

@array 		= qw(x x y z z z);
@out		= (0);
$lastValue 	= $array[0];

for ($iIndex = 0; $iIndex <= $#array; $iIndex++) {

	$thisValue = $array[$iIndex];
	
	if ($thisValue ne $lastValue) {
		push @out, ($iIndex - 1, $iIndex);
		$lastValue = $thisValue;
	}

}

push @out, $#array;

print Dumper(\@out);