code: public int get(String key, int start)
      {
          assert key != null;
          assert 0 <= start && start <= key.length();
          int state = 1;
          int[] ids = charMap.toIdList(key.substring(start));
          state = transfer(state, ids);
          if (state < 0)
          {
              return -1;
          }
          return stateValue(state);
      }
docs: 精确查询
  
  @param key
  @param start
  @return -1表示不存在