$f = file('words.txt');  $words = array();  foreach ($f as $w) {      $words[] = preg_quote(trim($w), '/');  }  $text = file_get_contents('text.txt');     $start = microtime(true);  $reg = '/' . implode('|', $words) . '/S';     preg_match_all($reg, $text, $m);     $result = array();  $total = 0;  foreach ($m[0] as $w) {      if (!isset($result[$w])) {          $result[$w] = 1;      } else {          $result[$w]++;      }      $total++;  }  $end = microtime(true);  echo $end - $start, "\n";  echo $total, "\n";     print_r($result);