Flippin'

flip.py

import random
import collections

COIN = ["H", "T"]

def average(array):
    return sum(array) / float(len(array))

def flip_coins(result):
    flips = collections.deque(maxlen=3)
    num_flips = 0

    while (list(flips) != result):
        flips.append(random.choice(COIN))
        num_flips += 1

    return num_flips

THT = []
HTT = []

for i in xrange(100000):
    THT.append(flip_coins(["T", "H", "T"]))
    HTT.append(flip_coins(["H", "T", "T"]))

print("THT average: " + str(average(THT)))
print("HTT average: " + str(average(HTT)))