Anders Ytterström
5be719dcf9
Tried to solve part 2 using BFS, but did not figure out a way to find shortest path. Fell back to a less elegant but more simple approach.
46 lines
1,015 B
Python
46 lines
1,015 B
Python
from collections import defaultdict, deque
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from output import answer, puzzleinput
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n = 6
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title = "Universal Orbit Map"
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@puzzleinput(n)
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def parse_input(data):
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heritage = defaultdict(str)
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for parent, child in [line.split(")") for line in data.split()]:
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heritage[child] = parent
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return heritage
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@answer(1, "{} direct and indirect orbits")
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def part_1(heritage):
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return sum(len(ancestry(heritage, v)) for v in heritage.keys())
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@answer(2, "Orbit transfers needed for you to share orbit with Santa: {}")
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def part_2(heritage):
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a = ancestry(heritage, "YOU")
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b = ancestry(heritage, "SAN")
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shared = len(set(a) & set(b))
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return sum(
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[
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len(a) - shared,
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len(b) - shared,
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]
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)
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def ancestry(parents, child):
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k = child
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lineage = []
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while k in parents:
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lineage.append(parents[k])
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k = parents[k]
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return lineage[::-1]
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if __name__ == "__main__":
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parsed = parse_input()
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part_1(parsed)
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part_2(parsed)
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