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from collections import defaultdict
State = set[tuple[int, int]]
def step(state: State) -> State:
def next_cell_state(x: int, y: int) -> bool:
neighbors = sum((x + dx, y + dy) in state for dx in (-1, 0, 1) for dy in (-1, 0, 1) if (dx, dy) != (0, 0))
if (x, y) in state:
return neighbors == 2 or neighbors == 3
else:
return neighbors == 3
next_state: State = set()
for x in range(100):
for y in range(100):
if next_cell_state(x, y):
next_state.add((x, y))
return next_state
def part1(state: State) -> int:
for i in range(100):
state = step(state)
return len(state)
def part2(state: State) -> int:
for i in range(100):
state = step(state)
state |= {(0, 0), (0, 99), (99, 0), (99, 99)}
return len(state)
if __name__ == '__main__':
with open('input') as f:
state: State = set()
for y, line in enumerate(f):
for x, c in enumerate(line.strip()):
if c == '#':
state.add((x, y))
print(part1(state))
print(part2(state))
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