45 lines
859 B
Crystal
45 lines
859 B
Crystal
require "advent"
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INPUT = input(2020, 7).lines.map(&.chomp).map do |s|
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data = s.match(/^([a-z ]+) bags contain (.*).$/).not_nil!
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{data[1], data[2].split(", ").map(&.rchop(" bags").rchop(" bag")) }
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end
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def build_graph(input)
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gr = Graph(String).new
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seen = Set(String).new
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input.each do |i|
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next if i[1] == ["no other"]
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seen << i[0]
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i[1].each do |to|
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n, _, m = to.partition(" ")
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n = n.to_i32
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gr.add_edge(i[0], m, n)
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end
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end
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{seen, gr}
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end
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def part1
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seen, gr = build_graph(INPUT)
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seen.count do |s|
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gr.find_path(s, "shiny gold") && s != "shiny gold"
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end
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end
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def count_bags(gr, current)
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return 1 unless es = gr.@edges[current]?
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1 + es.sum do |e|
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t, k = e
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k * count_bags(gr, t)
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end
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end
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def part2
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seen, gr = build_graph(INPUT)
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count_bags(gr, "shiny gold") - 1
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end
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puts part1
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puts part2
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