keys the same values ​​different GET parameters

this way, form the link differently ... you can parse the URL as a string and pull all the matches - but this is very ugly and crutch. You can get the entire query string in $ _SERVER ['QUERY_STRING'] and already parse it ...

 $ url = parse_url ('https://auto.yandex.ru/offers?sort_offers=relevance-desc&mark=audi&mark=toyota&mark=bmw');
 if (preg_match_all ("/ (? P [\ w \ - \ _] +) = (? P [^ = &] +) / isu", $ url ['query'], $ matches, PREG_SET_ORDER)) {
     $ url ['query'] = [];
     foreach ($ matches as $ item) {
         $ item ['value'] = urldecode ($ item ['value']);
         if (! isset ($ url ['query'] [$ item ['key']])) {
             $ url ['query'] [$ item ['key']] = $ item ['value'];
             continue;
         }

         if (! is_array ($ url ['query'] [$ item ['key']])) {
             $ url ['query'] [$ item ['key']] = [$ url ['query'] [$ item ['key']], $ item ['value']];
         } else {
             $ url ['query'] [$ item ['key']] [] = $ item ['value'];
         }
     }
 }
 var_dump ($ url);
 / **
 array (4) {
   ["scheme"] =>
   string (5) "https"
   ["host"] =>
   string (14) "auto.yandex.ru"
   ["path"] =>
   string (7) "/ offers"
   ["query"] =>
   array (2) {
     ["sort_offers"] =>
     string (14) "relevance-desc"
     ["mark"] =>
     array (3) {
       [0] =>
       string (4) "audi"
       [1] =>
       string (6) "toyota"
       [2] =>
       string (3) "bmw"
     }
   }
 }
 ** /

if it is possible to change the programming language for the implementation of this task, then use for example python + Flask to get the het parameters like this:

 request.args.getlist('r') 

Like so

 foreach($_GET as $key => $value){ echo $key." = ".$value."</br>"; } 

But all the last value alone will remain

So try, you should put in the array $ _GET ['r'] all 3 values

http: //test.loc/? r [] = 1 & r [] = 2 & r [] = 3