指定范围内少量不重复随机数生成

function runtime($mode = 0) {
    static $t;
    if(!$mode) {
        $t = microtime();
        return;
    }
    $t1 = microtime();
    $arr_t0 = explode(" ",$t);
    $arr_t1 = explode(" ",$t1);
    return sprintf("%.3f ms",(array_sum($arr_t1)-array_sum($arr_t0))*1000);
}

$range['max'] = 100;
$range['min'] = 1;

runtime();
$arr_dict = range($range['min'],$range['max']);
echo runtime(1)."n";

runtime();
list($first, $second) = array_rand($arr_dict,2);
echo runtime(2)."n";

runtime();
shuffle($arr_dict);
echo runtime(3)."n";

runtime();
mt_rand($range['min'],$range['max']);
echo runtime(4)."n";

runtime();
$mt_rand_my = function ($start,$end,$count){
        while($count){
                $arr[] = mt_rand($start,$end);
                if(count(array_unique($arr))>count($arr)) continue;
                $count -- ;
        }
        return $arr;
};
$res = $mt_rand_my($range['min'],$range['max'],2);
echo runtime(5)."n";