code: public Vertex get(int line, int length)
      {
          for (Vertex vertex : vertexes[line])
          {
              if (vertex.realWord.length() == length)
              {
                  return vertex;
              }
          }
  
          return null;
      }
docs: 获取某一行长度为length的节点
  
  @param line
  @param length
  @return