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from utils import open_day
bg = False
img = dict()
with open_day(20) as f:
first, rest = f.read().rstrip().split('\n\n')
alg = [c == '#' for c in first]
for y, line in enumerate(rest.split('\n')):
for x, c in enumerate(line):
img[(x, y)] = c == '#'
def bits_at(img, x, y):
bits = []
for dx, dy in ((-1, -1), (0, -1), (1, -1), (-1, 0), (0, 0), (1, 0), (-1, 1), (0, 1), (1, 1)):
bits.append(img.get((x + dx, y + dy), bg))
val = int(''.join('1' if b else '0' for b in bits), 2)
return val
def iter():
global bg, img
new = dict()
minx, maxx = float('inf'), float('-inf')
miny, maxy = float('inf'), float('-inf')
for p, v in img.items():
if not v: continue
x, y = p
minx, maxx = min(minx, x), max(maxx, x)
miny, maxy = min(miny, y), max(maxy, y)
for y in range(miny - 1, maxy + 2):
for x in range(minx - 1, maxx + 2):
new[(x, y)] = alg[bits_at(img, x, y)]
img = new
bg = not bg
iter()
iter()
print(sum(img.values()))
for _ in range(48): iter()
print(sum(img.values()))
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