AOC 2020 day 20

aoc_2020_day20_part1.py

import functools
import operator


def is_match(s, o):
    if s.raw == o.raw:
        return True
    if s.raw[::-1] == o.raw:
        return True
    return False


class Side:
    def __init__(self, n):
        self.raw = n
        self.matches = False
        self._tile = None

        self.matching_side = None

    def __eq__(self, other):
        if self._tile is other._tile:
            return False
        else:
            x = is_match(self, other)
            if x:
                self.matching_side = other
            return x

class Tile:
    def __init__(self, n):

        til, string = n.split(':\n')

        self.id = int(til.split(' ')[-1])

        self.raw = string
        self.sides = s = []

        x = string.splitlines()
        s.append(Side(x[0]))
        s.append(Side(x[-1]))

        s.append(Side(''.join(map(lambda t: t[0], x))))
        s.append(Side(''.join(map(lambda t: t[-1], x))))

        for side in self.sides:
            side._tile = self

    @property
    def num_matches(self):
        return sum(map(lambda m: m.matches, self.sides))


tiles = [*map(Tile, inp.split('\n\n'))]

for tile in tiles:
    for side in tile.sides:
        if any(os == side for ot in tiles for os in ot.sides):
            side.matches = True

corners = [tile for tile in tiles if tile.num_matches == 2]
print('part 1:', functools.reduce(operator.mul, map(lambda t: t.id, corners)))