code: public List<int[]> getNPaths(int n)
      {
          List<int[]> result = new ArrayList<int[]>();
  
          n = Math.min(Predefine.MAX_SEGMENT_NUM, n);
          for (int i = 0; i < N && result.size() < n; ++i)
          {
              List<int[]> pathList = getPaths(i);
              for (int[] path : pathList)
              {
                  if (result.size() == n) break;
                  result.add(path);
              }
          }
  
          return result;
      }
docs: 从短到长获取至多 n 条路径
  @param n
  @return