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79 lines
1.5 KiB
79 lines
1.5 KiB
1 week ago
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require "bundler/inline"
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gemfile do
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source "https://rubygems.org"
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gem "z3"
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end
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input = DATA.read
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machines = input.split("\n\n")
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.map {|machine| machine.scan(/\d+/).map(&:to_i) }
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wins = ->(machine) {
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ax, ay = machine[0,2]
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bx, by = machine[2,2]
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cx, cy = machine[4,2]
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(0..cx/ax).filter_map {|a|
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b = (cx - a * ax) / bx.to_f
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if a * ax + b.to_i * bx == cx && a * ay + b.to_i * by == cy
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[a, b.to_i]
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else
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nil
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end
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}.sort_by {|a,b| a + b }
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}
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pp machines.map { wins[_1].first }.compact.sum { 3 * _1 + _2 }
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require "z3"
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machines.each do |machine|
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machine[4,2] = machine[4,2].map { _1 + 10_000_000_000_000 }
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end
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def wins(machine)
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return enum_for(__method__, machine) unless block_given?
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ax, ay = machine[0,2]
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bx, by = machine[2,2]
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cx, cy = machine[4,2]
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solutions = []
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loop do
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a = Z3.Int("a")
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b = Z3.Int("b")
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solver = Z3::Solver.new
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solver.assert cx == a*ax + b*bx
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solver.assert cy == a*ay + b*by
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solutions.each do |a_s, b_s|
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solver.assert a != a_s
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end
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return unless solver.satisfiable?
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model = solver.model
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solutions << [model[a].to_i, model[b].to_i]
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yield solutions.last
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end
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end
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pp machines.flat_map {|m| wins(m).sort_by { _1 + _2 } }.reject(&:empty?).sum { 3 * _1 + _2 }
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__END__
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Button A: X+94, Y+34
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Button B: X+22, Y+67
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Prize: X=8400, Y=5400
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Button A: X+26, Y+66
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Button B: X+67, Y+21
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Prize: X=12748, Y=12176
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Button A: X+17, Y+86
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Button B: X+84, Y+37
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Prize: X=7870, Y=6450
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Button A: X+69, Y+23
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Button B: X+27, Y+71
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Prize: X=18641, Y=10279
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