php 2分查找算法

二分查找算法function bin_sch($array, $low, $high, $k){	   if ($low <= $high){	$mid = intval(($low+$high)/2);		if ($array[$mid] == $k){	return $mid;	}elseif ($k < $array[$mid]){		return bin_sch($array, $low, $mid-1, $k);	}else{		return bin_sch($array, $mid+1, $high, $k);	}   }	return -1;}