思路参考http://blog.csdn.net/wongson/article/details/7974587的Markov Chain回答。
ans = 0 for i in range(1000): a = b = c = cnt = 0 while a < 1&nbs***bsp;b < 1&nbs***bsp;c < 1: x = random.choice(seq) if x == 1: a += 1 elif x == 2: b += 1 else: c += 1 cnt += 1 ans += cnt print(ans / 1000)