public function highestHappinessChange(array $people)
 {
     $keys = array_keys($people);
     $highest = null;
     $table = null;
     foreach ($this->permutations->calculate($keys) as $k => $permutation) {
         $peopleAtTable = [];
         foreach ($permutation as $index) {
             $peopleAtTable[] = $people[$index];
         }
         $table = new Table($peopleAtTable);
         if (!$highest || $table->happinessChange() > $highest->happinessChange()) {
             $highest = $table;
         }
     }
     return $highest;
 }