code: public static <T extends Comparable<T>> List<T> topp(final T[] a, final int fromIndex, final int toIndex, final int n) {
          return topp(a, fromIndex, toIndex, n, N.NATURAL_ORDER);
      }
docs: The present order is kept in the result list.
  
  @param a
  @param fromIndex
  @param toIndex
  @param n
  @return