diff options
| -rw-r--r-- | 20.py | 42 |
1 files changed, 42 insertions, 0 deletions
@@ -0,0 +1,42 @@ +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())) |