private ArrayList RemoveDuplicateNum(ArrayList list)
    {
      list.Sort();
      for (int i = 0; i < list.Count - 1; i++)
      {
        if (list[i].Equals(list[i + 1]))
        {
          list.RemoveAt(i);//去重复项 
          i--;
        }
      }
      return list;

    }

    private ArrayList RemoveSame(ArrayList list)
    {
      //上面写的那句是多余的，这个是最终的 
      for (int i = 0; i < list.Count - 1; i++)
      {
        for (int j = i + 1; j < list.Count; j++)
        {
          if (list[i].Equals(list[j]))
          {
            list.RemoveAt(j);
            j--;
          }
        }
      }
      return list;
    }