30 lines
680 B
Python
30 lines
680 B
Python
import itertools
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import math
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import sys
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lines = sys.stdin.read().splitlines()
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sequence = lines[0]
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nodes = {
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p[0]: {d: n for d, n in zip("LR", p[1].strip("()").split(", "))}
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for line in lines[2:]
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if (p := line.split(" = "))
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}
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def path(start: str):
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path = [start]
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it_seq = iter(itertools.cycle(sequence))
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while not path[-1].endswith("Z"):
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path.append(nodes[path[-1]][next(it_seq)])
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return path
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# part 1
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answer_1 = len(path(next(node for node in nodes if node.endswith("A")))) - 1
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print(f"answer 1 is {answer_1}")
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# part 2
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answer_2 = math.lcm(*(len(path(node)) - 1 for node in nodes if node.endswith("A")))
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print(f"answer 2 is {answer_2}")
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