code: public static int invertedCompare(Solution s1, Solution s2) {
        int flag = InvertedCompareUtils.RankCompare(s1, s2);
  
        if (flag == 0)
        {
           flag = InvertedCompareUtils.CrowdingDistanceCompare(s1, s2);
        }
        return flag;
     }
docs: return -1 if s2 is better