判断网址是否被百度收录的代码

如何判断网址是否被百度收录呢？

function BD_cURL($url){
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, 'http://www.baidu.com/s?wd=' . $url . '');
    $httpheader[] = "Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8";
    $httpheader[] = "Accept-Encoding: gzip, deflate, sdch, br";
    $httpheader[] = "Accept-Language: zh-CN,zh;q=0.8";
    curl_setopt($ch, CURLOPT_HTTPHEADER, $httpheader);
    curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.106 Safari/537.3");
    curl_setopt($ch, CURLOPT_TIMEOUT, 3);
    curl_setopt($ch, CURLOPT_ENCODING, "gzip");
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    $ret = curl_exec($ch);
    curl_close($ch);
    if (!strpos($ret, '>百度为您找到相关结果约')) {
        return false;
    }
    if (!strpos($ret, '>提交网址')) {
        return true;
    }
    else {
        return false;
    }
}
echo BD_cURL('https://www.yqll.com/');