Creating a random number generator from a coin toss

Question

Yesterday i had this interview question, which I couldn\'t fully answer:

Given a function f() = 0 or 1 with a perfect 1:1 distribution, create a functio

Answer 1

def gen(a, b):
  min_possible = a
  max_possible = b

  while True:
    floor_min_possible = floor(min_possible)
    floor_max_possible = floor(max_possible)
    if max_possible.is_integer():
      floor_max_possible -= 1

    if floor_max_possible == floor_min_possible:
      return floor_max_possible

    mid = (min_possible + max_possible)/2
    if coin_flip():
      min_possible = mid
    else:
      max_possible = mid