day8.py

from typing import List

import aoc


def read_layers(data: List[int], width: int, height: int):
    size = width * height
    for layer in range(len(data) // size):
        yield Layer(data[size * layer:size * (layer + 1)], width, height)


class Layer:
    def __init__(self, pixels: List[int], width: int, height: int):
        self.pixels = pixels
        self.width = width
        self.height = height

        self.__iter__ = self.pixels.__iter__

    def render(self):
        rows = []
        for row in range(self.height):
            rows.append(''.join(map(str, self.pixels[row * self.width:(row + 1) * self.width])))
        return '\n'.join(rows).replace('0', ' ').replace('1', '\u2588')


class Image:
    def __init__(self, pixels: List[int], width: int, height: int):
        self.layers = list(read_layers(pixels, width, height))
        self.width = width
        self.height = height

    def merge(self):
        image = self.layers[0].pixels.copy()
        for layer in self.layers[1:]:
            for i, pixel in enumerate(layer.pixels):
                if image[i] == 2:
                    image[i] = pixel
        return Layer(image, self.width, self.height)


def main():
    with aoc.open_input(__name__) as f:
        data = [int(i) for i in f.read()]

    image = Image(data, 25, 6)
    print(calculate(image))
    print(image.merge().render())


def test():
    data = [int(i) for i in '123456789012']
    image = Image(data, 3, 2)
    print(calculate(image))

    data = [int(i) for i in '0222112222120000']
    image = Image(data, 2, 2)
    print(image.merge().render())


def calculate(image: Image) -> int:
    layer = min(image.layers, key=lambda l: l.pixels.count(0))
    num_1s = layer.pixels.count(1)
    num_2s = layer.pixels.count(2)

    return num_1s * num_2s