005.PHP实现二分查找

PHP实现二分查找

<?phpfunction midSch($arr,$key,$up,$down){if($up<=$down){$mid=intval(($up+$down)/2);if($key==$arr[$mid])return $mid;elseif($key<$arr[$mid])return midSch($arr,$key,$up,$mid-1);elsereturn midSch($arr,$key,$mid+1,$down);}return -1;}$arr=array(1,2,3,4,5,6,7,8,9,10,11,12);$rs=midSch($arr,11,0,count($arr)-1);echo $rs;?>