function ball_switch_board ($A, $k) {
    $score = 0;

    $Y_MAX = count($A) -1;
    $X_MAX = count($A[0]) -1;

    for ($k; $k > 0 ; $k --) {
        $x = 0;
        $y = 0;
        $dir = -1;

        while ($x <= $X_MAX && $y <= $Y_MAX) {
            $x_pos = $x;
            $y_pos = $y;

            $move = $A[$y][$x];

            switch ($move) {
                case 0:
                    $move = $dir;
                case -1:
                    $y ++;
                    break;
                case 1:
                    $x ++;
                    break;
            }

            $dir = move;

            $A[$y_pos][$x_pos] = (-1 * $A[$y_pos][$x_pos]);
        }

        if ($x == $X_MAX && $y > $Y_MAX) {
            $score ++;
        }
    }

    return $score;
}