"""Helpers for polyb.dc: polynomial evaluation per Mou 1991 Algo 4.7.

   shuffled(N): a random permutation of [0..2**N - 1] - test input."""

import random

def shuffled(N, seed=None):
    if seed is not None:
        random.seed(seed)
    arr = list(range(2 ** N))
    random.shuffle(arr)
    return arr