/**
* Determine the total happiness change by two knights sitting next to each other.
*
* @param Knight $knight1
* @param Knight $knight2
*
* @return int
*/
private function calculateHappinessChange($knight1, $knight2)
{
$knight1Happiness = $knight1->getHappiness($knight2);
$knight2Happiness = $knight2->getHappiness($knight1);
return $knight1Happiness + $knight2Happiness;
}
