ProjectEulerPy/p026.py at master · guoheng/ProjectEulerPy · GitHub

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#A unit fraction contains 1 in the numerator. The decimal representation of the unit fractions with denominators 2 to 10 are given:
#
#    1/2    =     0.5
#    1/3    =     0.(3)
#    1/4    =     0.25
#    1/5    =     0.2
#    1/6    =     0.1(6)
#    1/7    =     0.(142857)
#    1/8    =     0.125
#    1/9    =     0.(1)
#    1/10    =     0.1
#
#Where 0.1(6) means 0.166666..., and has a 1-digit recurring cycle. It can be seen that 1/7 has a 6-digit recurring cycle.
#
#Find the value of d < 1000 for which 1/d contains the longest recurring cycle in its decimal fraction part.

import logging

def RecurringCycle(n):
    d = []
    while (n > 0):
        d.append(n % 10)
        n = n//10
    for i in range(6,1000):
        if (d[0:i] == d[i:i*2]):
            return i
    logging.debug(d)
    assert(0)

def main(args):
    f = 10**2000
    maxrc = 6
    maxd = 7
    for d in range(11, 1000):
        rc = RecurringCycle(f//d)
        if (rc > maxrc):
            maxrc = rc
            maxd  = d

    logging.info("d = {}".format(maxd))
    logging.debug(maxrc)