php二分查找

bin_sch.php

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;
}