aoc21/day20.py at master · wesleyd/aoc21 · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
#!/usr/bin/env python3

from dataclasses import dataclass

test_input = """\
..#.#..#####.#.#.#.###.##.....###.##.#..###.####..#####..#....#..#..##..##
#..######.###...####..#..#####..##..#.#####...##.#.#..#.##..#.#......#.###
.######.###.####...#.##.##..#..#..#####.....#.#....###..#.##......#.....#.
.#..#..##..#...##.######.####.####.#.#...#.......#..#.#.#...####.##.#.....
.#..#...##.#.##..#...##.#.##..###.#......#.#.......#.#.#.####.###.##...#..
...####.#..#..#.##.#....##..#.####....##...##..#...#......#.#.......#.....
..##..####..#...#.#.#...##..#.#..###..#####........#..####......#..#

#..#.
#....
##..#
..#..
..###
"""

@dataclass
class Image:
    data: dict
    background: str
    def at(self, x: int, y :int):
        return self.data.get((x,y), self.background)

def parse_algo(input: str):
    first, _ = input.split('\n\n')
    return ''.join(first.splitlines())
assert len(parse_algo(test_input)) == 512

def parse_image(input: str):
    first, rest = input.split('\n\n')
    background = '.'
    data = {}
    for y, line in enumerate(rest.splitlines()):
        for x, c in enumerate(line):
            data[(x,y)] = c
    image = Image(data, background)
    return image
assert parse_image(test_input).at(0,0) == '#'
assert parse_image(test_input).at(-1000,-10000) == '.'

def nlit(image: Image):
    if image.background == '#':
        return float('inf')
    return sum([1 if c == '#' else 0 for c in image.data.values()])
assert nlit(parse_image(test_input)) == 10

def bounds(image: Image):
    left, right, top, bottom = 0, 0, 0, 0
    for x,y in image.data.keys():
        if x < left:
            left = x
        if x+1 > right:
            right = x+1
        if y < top:
            top = y
        if y+1 > bottom:
            bottom = y+1
    return (left, right, top, bottom)
assert bounds(parse_image(test_input)) == (0, 5, 0, 5)

def resolve(image: Image, x: int, y: int):
    cc = [
        image.at(x-1, y-1), image.at(x, y-1), image.at(x+1,y-1),
        image.at(x-1, y),   image.at(x, y),   image.at(x+1,y),
        image.at(x-1, y+1), image.at(x, y+1), image.at(x+1,y+1),
    ]
    s = ''.join(cc)
    return int(s.replace('#', '1').replace('.', '0'), 2)
assert resolve(parse_image(test_input), 2, 2) == 34

def strimage(image: Image):
    left, right, top, bottom = bounds(image)
    lines = []
    for y in range(top, bottom):
        line = []
        for x in range(left, right):
            line.append(image.at(x, y))
        lines.append(''.join(line))
    return '\n'.join(lines)
assert strimage(parse_image(test_input)) == """\
#..#.
#....
##..#
..#..
..###"""

def enhance(before: Image, algo: list):
    left, right, top, bottom = bounds(before)
    data = {}
    for y in range(top-1, bottom+1):
        for x in range(left-1, right+1):
            r = resolve(before, x, y)
            data[(x,y)] = algo[r]
    r = resolve(before, float('inf'), float('inf'))
    background = algo[resolve(before, float('inf'), float('inf'))]
    return Image(data, background)
assert (strimage(enhance(parse_image(test_input), parse_algo(test_input)))) == """\
.##.##.
#..#.#.
##.#..#
####..#
.#..##.
..##..#
...#.#."""

def enhanceN(img: Image, algo: list, n: int):
    for i in range(n):
        img = enhance(img, algo)
    return img
assert strimage(enhanceN(parse_image(test_input), parse_algo(test_input), 2)) == """\
.......#.
.#..#.#..
#.#...###
#...##.#.
#.....#.#
.#.#####.
..#.#####
...##.##.
....###.."""

with open('inputs/day20.input') as f:
    day20_input = f.read()
    day20_algo = parse_algo(day20_input)
    day20_image = parse_image(day20_input)
    day20_after2 = enhanceN(day20_image, day20_algo, 2)
    print('Day 20 part 1 => %d' % nlit(day20_after2))

# Part 2

assert nlit(enhanceN(parse_image(test_input), parse_algo(test_input), 50)) == 3351
with open('inputs/day20.input') as f:
    day20_input = f.read()
    day20_algo = parse_algo(day20_input)
    day20_image = parse_image(day20_input)
    day20_after50 = enhanceN(day20_image, day20_algo, 50)
    print('Day 20 part 2 => %d' % nlit(day20_after50))