二维组合连乘相加

function award_sp_cal($spRzt) {
    $totalAward = 1;
    $temp = null;
    foreach($spRzt as $sp) {
        if (count($sp) == 1) {
            $totalAward *= array_shift($sp);
        } else if (count($sp) >1 ) {
            $temp = $totalAward;
            $totalAward = 0;//原理: a*x + b*x = (a+b)*x
            foreach($sp as $spOne) {
                $totalAward += ($temp*$spOne);
            }
        }
    }
    
    return $totalAward;
}

$arr = array(array(1,2,3), array(2), array(3));
//结果为array(1,2,3), array(2,2,3), array(3,2,3)的组合之和
echo award_sp_cal($arr);