advent-of-code/2017-python/solutions/day_15.py

from solutions import BaseSolution


class Solution(BaseSolution):
    input_file = "15.txt"

    def __str__(self):
        return "Day 15: Dueling Generators"

    def _calc(self, x, f, m=1):
        x = (x * f) % 2147483647
        if x % m != 0:
            return self._calc(x, f, m)
        else:
            return x

    def solve(self, puzzle_input):
        af, bf = (16807, 48271)
        a, b = [int(pi.split()[-1]) for pi in puzzle_input.splitlines()]
        j = 0
        for _ in range(40 * 10**6):
            a = self._calc(a, af)
            b = self._calc(b, bf)
            if "{:b}".format(a)[-16:] == "{:b}".format(b)[-16:]:
                j += 1
        return j

    def solve_again(self, puzzle_input):
        af, bf = (16807, 48271)
        a, b = [int(pi.split()[-1]) for pi in puzzle_input.splitlines()]
        j = 0
        for _ in range(5 * 10**6):
            a = self._calc(a, af, 4)
            b = self._calc(b, bf, 8)
            if "{:b}".format(a)[-16:] == "{:b}".format(b)[-16:]:
                j += 1
        return j


if __name__ == "__main__":
    solution = Solution()
    solution.show_results()