49 lines
1.2 KiB
Ruby
49 lines
1.2 KiB
Ruby
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class PotentialTriangle
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attr_reader :sides
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def initialize(line)
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@sides = line.split.map(&:to_i)
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end
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%w[a b c].each_with_index do |side, index|
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define_method("side_#{side}") do
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sides[index]
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end
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end
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def valid?
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side_a_valid? && side_b_valid? && side_c_valid?
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end
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def side_a_valid?
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side_a < side_b + side_c
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end
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def side_b_valid?
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side_b < side_a + side_c
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end
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def side_c_valid?
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side_c < side_b + side_a
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end
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end
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input = STDIN.read.chomp
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potential_triangle_lines = input.split("\n")
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potential_triangles = potential_triangle_lines.map { |line| PotentialTriangle.new line }
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valid_triangles = potential_triangles.count(&:valid?)
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puts "Part 1: #{valid_triangles}"
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grouped_triangle_lines = potential_triangle_lines.join(" ").split.each_with_index.each_with_object([[], [], []]) do |item_index, groups|
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item, index = item_index
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groups[index % 3] << item
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groups
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end
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sideways_triangle_lines = grouped_triangle_lines.flatten.each_slice(3).to_a.map { |tri| tri.join " " }
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sideways_triangles = sideways_triangle_lines.map { |line| PotentialTriangle.new line }
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valid_sideways_triangles = sideways_triangles.count(&:valid?)
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puts "Part 2: #{valid_sideways_triangles}"
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