public function binarySearch($arr, $item) {
        $low = 0;
        $hight = count($arr) - 1;


        while ($low <= $hight) {
            $mid = $low + $hight;
            $guess = $arr[$mid];
            if ($guess == $item) {
                return $mid;

            } elseif ($guess > $item) {
                $hight = $mid - 1;
            } elseif ($guess < $item) {
                $low = $mid + 1;
            }
        }
    }