php随机概率红包算法

 /**
     * @param $num
     * @param $total
     * @param int $range  差距是否大
     * @return array|int
     */
    private function randomSplit($num,$total,$range=1){

        if($num<2){
            return $total;
        }

        $p=array();

        $min=floor($total/$num-$range);
        $max=floor($total/$num+$range);
        for($i=0;$i<$num-1;$i++){
            $depart=mt_rand($min,$max);
            $p[]=$depart;
            $total-=$depart;
        }
        $p[]=$total;
        return $p;

    }