[面试题] 等概率生成器

题目：已知一随机发生器，产生0的概率是p，产生1的概率是1-p，现在要你构造一个发生器，使得它构造0和1的概率均为1/2；

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import random p = 200 def generate(p):     n = random.randrange(0, 1000)     res = 0     if n > p:         return 0     else:         return 1   def generate_01(): # 生成 0 和 1 等概率     n1 = generate(p)     n2 = generate(p)     if (n1 == 0 and n2 == 1):         return 1     if (n1 == 1 and n2 == 0):         return 0     return generate_01()   l1 = 0 l0 = 0 for i in range(1000):     x = generate_01()     if x == 1:         l1 += 1     if x == 0:         l0 += 1   print("l0:", l0) print("l1", l1)