28 lines
561 B
Python
28 lines
561 B
Python
from collections import defaultdict
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with open("input/day12.txt") as f:
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input = f.read()
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neighbors = defaultdict(set)
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for line in input.splitlines():
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a, bs = line.split(" <-> ")
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for b in bs.split(", "):
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neighbors[a].add(b)
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neighbors[b].add(a)
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def connected(start, neighbors) -> int:
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queue = [start]
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seen = set()
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while queue:
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node = queue.pop(0)
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if node in seen:
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continue
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seen.add(node)
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queue.extend(neighbors[node])
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return len(seen)
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print(connected("0", neighbors))
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