62 lines
1.6 KiB
Python
62 lines
1.6 KiB
Python
from lib import *
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input = read_input(2020, 11)
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lines = input.splitlines()
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graph = {}
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active = set()
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for y, line in enumerate(lines):
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for x, c in enumerate(line):
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if c == ".":
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continue
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graph[(x, y)] = []
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for dy in range(-1, 2):
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for dx in range(-1, 2):
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if dx == 0 == dy:
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continue
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if 0 <= (i := y + dy) < len(lines) and 0 <= (j := x + dx) < len(line) and lines[i][j] != ".":
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graph[(x, y)].append((j, i))
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while True:
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new_active = set()
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for p, qs in graph.items():
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cnt = sum(q in active for q in qs)
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if p not in active and not cnt or p in active and cnt < 4:
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new_active.add(p)
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if active == new_active:
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break
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active = new_active
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print(len(active))
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graph = {}
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active = set()
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for y, line in enumerate(lines):
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for x, c in enumerate(line):
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if c == ".":
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continue
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graph[(x, y)] = []
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for dy in range(-1, 2):
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for dx in range(-1, 2):
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if dx == 0 == dy:
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continue
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k = 1
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while 0 <= (i := y + k * dy) < len(lines) and 0 <= (j := x + k * dx) < len(line):
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if lines[i][j] != ".":
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graph[(x, y)].append((j, i))
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break
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k += 1
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while True:
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new_active = set()
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for p, qs in graph.items():
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cnt = sum(q in active for q in qs)
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if p not in active and not cnt or p in active and cnt < 5:
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new_active.add(p)
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if active == new_active:
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break
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active = new_active
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print(len(active))
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