オフラインリアルタイムどう書くE06 の問題への yancya の回答
時間内に解けなかった辛い
class Monster
  ELEMENTS = {
         # に弱い に強い
    'B' => ['G', 'R'],
    'G' => ['R', 'B'],
    'R' => ['B', 'G']
  }

  attr_accessor :level, :element, :hp

  def initialize(str)
    @level  = str.scan(/^\d+/).first.to_i
    @element = str.scan(/\w$/).first
    @hp = @level
  end

  def cure!
    @hp = @level
  end

  def battle!(opponent)
    match = [self, opponent]

    until match.any?(&:dead?)
      case
      when @level > opponent.level
        attack(opponent)
        return if opponent.dead?
        opponent.attack(self)
      when opponent.level > @level
        opponent.attack(self)
        return if dead?
        attack(opponent)
      else
        opponent.attack(self)
        attack(opponent)
      end
    end
  end

  def dead?
    @hp < 1
  end

  def attack(opponent)
    damage = case opponent.element     # 相手モンスターが
             when element              # 同じ属性だったら
               2
             when ELEMENTS[element][0] # 苦手属性だったら
               1
             when ELEMENTS[element][1] # 得意属性だったら
               4
             else
               raise "なにがあった？"
             end

    opponent.kurau!(damage)
  end

  def kurau!(damage)
    @hp -= damage
  end
end

class Trainer
  attr_accessor :id, :monsters

  def initialize(id, monsters)
    @id = id
    @monsters = monsters
  end

  def lose?
    ready_monsters.empty?
  end

  def ready_monsters
    monsters.reject(&:dead?)
  end

  def battle!(opponent)
    match = [self, opponent]

    match.
      map(&:monsters).
      reduce(:+).
      each(&:cure!)

    until match.any?(&:lose?)
      match.
        map(&:ready_monsters).
        map(&:first).
        reduce(:battle!)
    end

    match.reject(&:lose?).first
  end
end

def execute(input)
  trainers =
    input.
      split(",").
      map.with_index(1) { |monsters, index|
    Trainer.new(
      index,
      monsters.scan(/\d+\w/).map { |s| Monster.new(s) }
    )
  }

  trainers.combination(2).
    map { |a, b| a.battle!(b) }.
    compact.
    group_by(&:itself).
    # 勝ち星の無い人を追加
    merge(trainers.map { |t| [t, []] }.to_h) { |_, o, _| o }.
    map { |trainer, win_matches| [trainer.id, win_matches.count] }.
    sort_by { |id, wins| [-wins, id] }.
    map(&:first).
    join(",")
end

require 'test-unit'

class HogeTest < Test::Unit::TestCase
  data(
    '/*0 */' => ["9B,3R2G,1R2B3G", "1,3,2"],
    '/*1 */' => ["1G", "1"],
    '/*2 */' => ["1G,1R,1B", "1,2,3"],
    '/*3 */' => ["8B,3R2G,1R2B3G", "3,1,2"],
    '/*4 */' => ["6G,9R7B7B", "2,1"],
    '/*5 */' => ["5B1B,1G1B2R6G,7B6G4B6B", "3,2,1"],
    '/*6 */' => ["7R,2R9G,6R4B1G6R,5G1G6G", "3,1,2,4"],
    '/*7 */' => ["2B9G8B3R,4R3G,2B,8B", "1,2,4,3"],
    '/*8 */' => ["1B,5G1R1B4R,5R,8B9B4G,7G5R8G", "5,4,3,2,1"],
    '/*9 */' => ["9G5B,6B6R1R5G,7G6G,8B5R,5G7G,2G5B7B", "2,1,3,4,5,6"],
    '/*10*/' => ["5B,1B8R2B,8G6R4B,4B1G6R8G,3B6G6G5R,7B", "3,4,5,6,1,2"],
    '/*11*/' => ["2G2G7G9B,6G5G5R,2G,4G,5R,3G8R,6G9R", "1,7,6,2,5,4,3"],
    '/*12*/' => ["6G7B4R6B,9R4G,6G5B5G3B,6R7G,9B,7G7B8R,5G8G2R,6B8G7B1B", "8,1,6,2,3,4,7,5"],
    '/*13*/' => ["9B8B2G4B,2B1R,7R6G8R,4R,1G7B7R,4B3B4R,4B3R2R4G,4G9R9R", "1,3,8,5,6,7,2,4"],
    '/*14*/' => ["5G,3G,9G7G8B,7B,8G6B1B5G,1G3B,5G8R,6G,7B", "3,5,7,8,1,2,4,9,6"],
    '/*15*/' => ["5B1R5B,6R,7R7R,8B1B,6R1G,7B3R2R,4R3B,6G1R8G,6B4R4R2B,9G5B", "10,1,4,6,9,3,8,5,7,2"],
    '/*16*/' => ["7R4G1G6R,9B3G3R4G,2G7G,5B,5R8R,9G7R9B,8R7R5G,7B9R1R8R,7R,9R1B", "6,8,7,2,1,5,4,10,3,9"],
    '/*17*/' => ["3G8B2B8G,7B7R5G,4B9G2R,4G,1G2R5R8R,1B,8R9G7G,7R6B,6B8B,3G3R,3R2R", "2,7,1,3,9,5,8,10,11,4,6"],
    '/*18*/' => ["5G3B,4B3G,7G8R2B7R,6G,1G,1B,1R9R2R7R,3R4G1R,4B3G2G8G,3B,2B1G,7R", "3,7,9,8,1,4,2,12,10,11,5,6"],
    '/*19*/' => ["4B2B5G1G,2G2B3R,7G4B9R9G,7R9G,5B,5G3G,7R5R,4B,6G3R4G3G,3R9G,8R9G4R,2R", "3,11,4,7,10,9,1,5,6,2,8,12"],
    '/*20*/' => ["8R,9R,5R,4G,3G2G1R,5G,4G5G,2G,6G6B1G,8R2G6B2G,1G5B8B,1G,7R", "10,9,2,1,11,13,3,7,6,4,5,8,12"],
    '/*21*/' => ["2R,4G7G,4R,1G1R7G,5B6G,2G,4B9R,7R2B7R4B,3B1G5G,8B9R,6B1G6R,1R2R,9G2B2R,4R9B", "10,11,14,8,13,5,7,2,3,4,9,1,12,6"],
    '/*22*/' => ["6R3R3B,1R,7R4B4G,7G9B,4G6G8B,4R7R4B,5R3R,3R,5B2G4R,1B,5B,9B2R,5G4R,6R3R3G", "4,3,5,12,9,14,6,11,1,13,7,8,2,10"],
    '/*23*/' => ["5B7B,8G,7G,6R9B3B,2B,3G3B8R7B,7R7G6R,4B6B5G,4R4G9R,4B7G6G5G,3B8B1B1G,5G7G2R,1B,2G6G5B3G,4R4B8B", "7,6,9,10,4,12,14,2,8,15,3,1,11,5,13"],
    '/*24*/' => ["8B9B,6R3B2G,5B,6R2R5R,3R1B,1R1R1B9B,4R4B9G9G,8R2B,6B,1B,2R,4B,6G7R,7G,3G2G7R,7B7G8G", "7,16,1,2,13,6,15,8,9,14,3,4,12,5,11,10"],
    '/*25*/' => ["8R,4G,8G5G,7G1R1R7R,6R,2G3B5B,7G3R1B,4B9G9G,5R4G5R7B,8B9B1B4G,5G9R1R,8B,7G1B,9B3R,2R9G,6G5G", "9,11,4,8,1,3,7,10,15,5,14,16,6,13,2,12"],
    '/*26*/' => ["1G3B8G,8R6B9B9B,7B,7R3B5G1B,3G,7B8G9B,2B2G6B6B,2B7G9R1B,2G8B6R8R,3R,9B3G5R2G,5B2R3R5B,8B4B,4G1R,2B,8R1B7B4R,9B", "6,2,9,11,8,1,4,7,16,12,17,13,14,3,5,10,15"],
    '/*27*/' => ["2B,6G1G6G4R,3B8B3B,9G,1R,3B,7R9G2R,6R1G4G6B,3B5G8G,8G1G3B4R,4G8G,6G2B5B,4G2G5R,1B,4G6G,3G1R9G,8B5R4B7R,4R3B", "7,8,17,10,2,9,13,16,18,4,12,11,15,3,6,1,5,14"],
    '/*28*/' => ["9G,6B3G1B4B,4B3R2R5G,2R1G,6B6R8B1R,4R3R1R,9R,8R8B,4G,3G9B,6G8B2R,5R8R6G,5B1B7B4B,2R3G1G3B,3R5B4R,8G5G,5G2B2R,8G", "5,11,12,3,8,15,10,16,1,7,2,13,6,18,14,17,4,9"],
    '/*29*/' => ["7B9R,2B3R1R2R,2G6B3G,6R,8G,6B7B6R,1R1G5B6G,9G,2R6G,7B6B9G5R,5G4G1B7B,4B9R2B5G,2G8B9G9G,8G3B5R,3G,2R,3R2B9B,8B3B,1R", "10,13,14,6,12,1,11,17,8,7,2,3,5,9,4,18,16,15,19"],
    '/*30*/' => ["8G6B9G,8G,7B4G2G6G,3B8R2R,4R1R3R8B,3G,2R1R,1R9G2B1G,4G8G,8B8B2R8R,2R1R1G,4B2B6R4B,6G9G3G6R,9B6B8R,9R7B,3G,5B4B,4B4G6B8B,4B5G,8B2R", "1,14,10,13,15,18,3,5,8,9,12,2,20,4,19,17,11,7,6,16"],
  )
  test "hoge" do |(actual, expected)|
    assert { execute(actual) == expected }
  end
end