AoC2020Day23pt2

day23pt2.py

from typing import List


class Link:
    def __init__(self, cup_num, next_link=None):
        self.cup_num: int = cup_num
        self.next_link: Link = next_link
        self.terminator = False

    def __repr__(self):
        return f'{self.cup_num}'


class ChainIter:
    def __init__(self, link: Link):
        self._link = link
        self._first = True

    def __next__(self):
        if self._first or not self._link.terminator:
            to_return = self._link
            self._link = self._link.next_link
            self._first = False
            return to_return
        raise StopIteration


class Chain:
    def __init__(self, cups: List[int]):
        self._cup_num_to_link = dict()
        self._cup_link = Link(cups[0])
        self._cup_link.terminator = True
        self._cup_num_to_link[self._cup_link.cup_num] = self._cup_link
        last_link = self._cup_link
        for cup_num in cups[1:]:
            next_link = Link(cup_num)
            self._cup_num_to_link[next_link.cup_num] = next_link
            last_link.next_link = next_link
            last_link = next_link
        last_link.next_link = self._cup_link

    def __iter__(self):
        return ChainIter(self._cup_link)

    def first(self):
        return self._cup_link

    def __getitem__(self, key):
        return self._cup_num_to_link[key]


class Ring:
    def __init__(self, cups: List[int], pad=False):
        self._min = min(*cups)
        self._max = max(*cups)
        if pad:
            for x in range(self._max + 1, 1000001):
                self._max = x
                cups.append(x)
        self._game_cnt = 1
        self._cups = Chain(cups)
        self._cur_cup = self._cups.first()


    def _find_target(self, cups_to_move):
        def is_good(cup):
            return cup not in cups_to_move and \
                   cup != self._cur_cup.cup_num and \
                   self._max >= cup >= self._min

        cup_to_find = self._cur_cup.cup_num
        while not is_good(cup_to_find):
            cup_to_find -= 1
            if cup_to_find < self._min:
                cup_to_find = self._max
        return cup_to_find


    def play_round(self):
        print(f'-- move {self._game_cnt} --')
        # print([c for c in self._cups])
        cur_cup = self._cur_cup
        cups_to_move = []
        next_link = cur_cup.next_link
        cups_to_move.append(next_link)
        for offset in range(0, 2):
            next_link = next_link.next_link
            cups_to_move.append(next_link)
        print(f'cur cup: {self._cur_cup}')
        print(f'pickup {cups_to_move}')
        skip_to_link = next_link.next_link
        cur_cup.next_link = skip_to_link
        target = self._find_target([cup.cup_num for cup in cups_to_move])
        print(f'destination: {target}')
        target_link = self._cups[target]
        target_link_next = target_link.next_link
        target_link.next_link = cups_to_move[0]
        cups_to_move[-1].next_link = target_link_next
        self._cur_cup = cur_cup.next_link
        self._game_cnt += 1

    def get_cup_order(self):
        nums = []
        link = self._cups[1]
        next_link = link.next_link
        while next_link.cup_num != 1:
            nums.append(next_link.cup_num)
            next_link = next_link.next_link
        return nums


def day23():
    ring = Ring([int(i) for i in list('394618527')], True)
    for idx in range(0, 10000000):
        ring.play_round()

    final_order = [i for i in ring.get_cup_order()]
    print(final_order[0])
    print(final_order[1])
    print(final_order[0] * final_order[1] )

if __name__ == '__main__':
    day23()