# The four adjacent digits in the 1000-digit number that have
# the greatest product are 9 x 9 x 8 x 9 = 5832.
#
# Find the thirteen adjacent digits in the 1000-digit number that have
# the greatest product. What is the value of this product?

from functools import reduce

number = \
"73167176531330624919225119674426574742355349194934\
96983520312774506326239578318016984801869478851843\
85861560789112949495459501737958331952853208805511\
12540698747158523863050715693290963295227443043557\
66896648950445244523161731856403098711121722383113\
62229893423380308135336276614282806444486645238749\
30358907296290491560440772390713810515859307960866\
70172427121883998797908792274921901699720888093776\
65727333001053367881220235421809751254540594752243\
52584907711670556013604839586446706324415722155397\
53697817977846174064955149290862569321978468622482\
83972241375657056057490261407972968652414535100474\
82166370484403199890008895243450658541227588666881\
16427171479924442928230863465674813919123162824586\
17866458359124566529476545682848912883142607690042\
24219022671055626321111109370544217506941658960408\
07198403850962455444362981230987879927244284909188\
84580156166097919133875499200524063689912560717606\
05886116467109405077541002256983155200055935729725\
71636269561882670428252483600823257530420752963450"
digits_to_consider = 13

class SummingQueue(object):

    def __init__(self, maxlen):
        self.maxlen = maxlen
        self.q = []

    def put(self, number):
        self.q.append(number)
        return self.q.pop(0) if len(self.q) > self.maxlen else None

    def product(self):
        return reduce(lambda x, y: x * y, self.q)

    def __str__(self):
        return str(self.q)

queue = SummingQueue(digits_to_consider)

greatest_product = 0
for ndx in range(len(number)):

    if ndx < digits_to_consider:
        queue.put(int(number[ndx]))

    else:

        if ndx == digits_to_consider:
            greatest_product = queue.product()

        added = int(number[ndx])
        removed = queue.put(added)

        if added > removed:
             candidate_product = queue.product()
             if candidate_product > greatest_product:
                 greatest_product = candidate_product

        print(queue)

print(greatest_product)
