二分查找（数组里查找某个元素） php php 二分查找

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; 
}