code: protected int transitionWithRoot(int nodePos, char c)
      {
          int b = base[nodePos];
          int p;
  
          p = b + c + 1;
          if (b != check[p])
          {
              if (nodePos == 0) return 0;
              return -1;
          }
  
          return p;
      }
docs: c转移，如果是根节点则返回自己
  
  @param nodePos
  @param c
  @return