第一种算法，CSDN上别人的想法
$num = 0;
$array = array(1, 2, 3, 4, 5, 6, 7, 8, 9);
$arr = array();
$g = 5;
$tag = true;
while ($tag) {
$count = count($array);
$t = rand(0, 1);
if ($t == 1) {
$arr[] = $array[$num];
unset($array[$num]);
}
$num ++;
if (count($arr) =
