private static <T> int maxSize(List<List<T>> items) {
    if (items.size() == 0) return 0;
    int maxsize = -1;
    for (List<T> item : items) {
      int size = item.size();
      if (maxsize < size) maxsize = size;
    }
    return maxsize;
  }
private static <T> int maxSize(List<List<T>> items)