euler/python/e026.py

from itertools import count


def get_cycle_count(nominator, denominator):
    assert(nominator == 1)
    remainders = {}
    remainder = nominator
    results = []
    for i in count():
        result = remainder // denominator
        remainder = remainder % denominator
        results.append(result)
        if remainder in remainders:
            return i - remainders[remainder]
        else:
            remainders[remainder] = i
        if remainder == 0:
            return 0
        remainder *= 10


def euler_026():
    return max([(get_cycle_count(1, i), i) for i in range(1, 1000)])[1]


if __name__ == "__main__":
    assert(get_cycle_count(1, 7) == 6)
    assert(get_cycle_count(1, 10) == 0)
    assert(get_cycle_count(1, 6) == 1)
    print("e026.py: {}".format(euler_026()))
    assert(euler_026() == 983)