code: private function computeConfigFiles()
      {
          $configFile = $this->options['config'];
  
          if (null !== $configFile) {
              if (false === file_exists($configFile) || false === is_readable($configFile)) {
                  throw new InvalidConfigurationException(sprintf('Cannot read config file "%s".', $configFile));
              }
  
              return [$configFile];
          }
  
          $path = $this->getPath();
  
          if ($this->isStdIn() || 0 === \count($path)) {
              $configDir = $this->cwd;
          } elseif (1 < \count($path)) {
              throw new InvalidConfigurationException('For multiple paths config parameter is required.');
          } elseif (is_file($path[0]) && $dirName = pathinfo($path[0], PATHINFO_DIRNAME)) {
              $configDir = $dirName;
          } else {
              $configDir = $path[0];
          }
  
          $candidates = [
              $configDir.\DIRECTORY_SEPARATOR.'.php_cs',
              $configDir.\DIRECTORY_SEPARATOR.'.php_cs.dist',
          ];
  
          if ($configDir !== $this->cwd) {
              $candidates[] = $this->cwd.\DIRECTORY_SEPARATOR.'.php_cs';
              $candidates[] = $this->cwd.\DIRECTORY_SEPARATOR.'.php_cs.dist';
          }
  
          return $candidates;
      }
docs: Compute file candidates for config file.
  
  @return string[]