My Advent of Code solutions in Python.
kevinyap.ca/2019/12/going-fast-in-advent-of-code/
advent-of-code
python
Add 2025/11
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+23
2025/day11.py
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2025/day11.py
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import fileinput
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from collections import defaultdict
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from functools import cache
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@cache
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def ways(start, end):
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if start == end:
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return 1
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return sum(ways(n, end) for n in GRAPH[start])
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# Read problem input.
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GRAPH = defaultdict(set)
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for line in fileinput.input():
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node, other = line.strip().split(': ')
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for b in other.split():
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GRAPH[node].add(b)
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# Solve problem.
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print("Part 1:", ways('you', 'out'))
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print("Part 2:", ways('svr', 'fft') * ways('fft', 'dac') * ways('dac', 'out'))
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