获得数组里的数字连号问题

mysql_connect();mysql_select_db('test');mysql_query('DROP TABLE IF EXISTS lookup');mysql_query('CREATE TABLE lookup (id INT, INDEX USING BTREE (id)) ENGINE = MEMORY');$a = array(1,3,5,6,7,8,9,10,14,15,18,100,101);foreach($a as $v) mysql_query("insert into lookup values ($v)");for($n=2; $n<5; $n++) {  echo "<h5>$n</h5>";  $rs = mysql_query("select a.id, group_concat(b.id) as grouping, count(*) as cnt from lookup a, lookup b where a.id<=b.id and a.id>b.id-$n group by a.id HAVING cnt=$n") or die(mysql_error());  while($row = mysql_fetch_assoc($rs)) {    echo $row['grouping'], '<br>';  }}

function LinkNum($array,$num){  if(count($array) < $num)  {      return 0;  }  $cishu = 0; //临时变量  $total = 0;  //N连号次数  for($i=0;$i<count($array);$i++)  {      if($array[$i] == $array[$i+1]-1)      {          $cishu++;          if($cishu == $num)          {              $i = $i+1;              $cishu = 0;          }      }      else      {          if($cishu == $num -1 && ($i - $num <= 0 || $array[$i] - $num != $array[$i - $num])) {              $total++;          }          $cishu = 0;      }  }  return $total;}echo "1,3,5,6,7,8,9,10,14,15,18,100,101".'有2连号'.LinkNum(array(1,3,5,6,7,8,9,10,14,15,18,100,101),2).'组'.'<br>';echo "1,3,5,6,7,8,9,10,14,15,18,100,101".'有3连号'.LinkNum(array(1,3,5,6,7,8,9,10,14,15,18,100,101),3).'组'.'<br>';echo "1,3,5,6,7,8,9,10,14,15,18,100,101".'有4连号'.LinkNum(array(1,3,5,6,7,8,9,10,14,15,18,100,101),4).'组'.'<br>';