随机分配红包算法

function redpacket($money_sum,$num_redpacket)
        {
            $max = ($money_sum / $num_redpacket) * 2;
            $packet = [];
            for (;$num_redpacket>0;$num_redpacket--)
            {
                if(1 == $num_redpacket)
                {
                    $packet[] = $money_sum;
                    continue;
                }
                (($_max = $money_sum - (($num_redpacket-1) * 0.01)) > $max) && $_max = $max;
                (($_min = $money_sum - (($num_redpacket-1) * $max)) < 0) && $min = 0;
                $rand = bcdiv(rand(bcmul($_min, 100), bcmul($_max, 100)), 100,2);
                $packet[] = $rand;
                $money_sum = bcsub($money_sum, $rand, 2);
            }
            return $packet;
        }