オフラインリアルタイムどう書く #14 の問題を解いた http://nabetani.sakura.ne.jp/hena/ord14linedung/

hunting_monsters.rb

require 'rspec'

module HuntingMonsters
  class Player
    attr_reader :weapons

    def initialize
      @weapons = []
    end

    def add_weapon weapon
      @weapons << weapon
    end

    def has_weapon? weapon
      @weapons.include? weapon
    end
  end

  class Monster
    attr_reader :symbol, :weak_weapon, :dropping_weapon

    def initialize symbol, weak_weapon, dropping_weapon
      @symbol           = symbol
      @weak_weapon      = weak_weapon
      @dropping_weapon  = dropping_weapon
      @live             = true
    end

    def live?
      @live
    end

    def die
      @live = false
    end
  end

  class Exercise
    # [シンボル, 倒せる武器, 落とす武器]
    MONSTERS_DATA = [
      ["B", "a", "c"],
      ["D", "c", "e"],
      ["F", "e", "g"],
      ["H", "g", "i"],
      ["J", "i", "k"],
      ["L", "k", "a"]
    ]

    def initialize input_value
      @player      = Player.new
      @monsters    = nil
      @input_value = input_value
    end

    def solve
      setting_weapons
      setting_monsters

      loop do
        target_monsters = @monsters.select { |monster| monster.live? && @player.has_weapon?(monster.weak_weapon) }
        break if target_monsters.size == 0

        target_monsters.each do |monster|
          monster.die
          @player.add_weapon(monster.dropping_weapon)
        end
      end

      @monsters.count { |monster| !monster.live? }
    end

    private

    def setting_weapons
      extract_weapons.uniq.each { |weapon| @player.add_weapon(weapon) }
    end

    def setting_monsters
      monsters_data = []

      MONSTERS_DATA.each do |monster_data|
        monsters_data << Monster.new(*monster_data)
      end

      @monsters = extract_monsters.map do |monster_symbol|
        monsters_data.find { |monster_data| monster_data.symbol == monster_symbol }
      end
    end

    def extract_weapons
      @input_value.chars.select { |char| char =~ %r{[a-z]} }
    end

    def extract_monsters
      @input_value.chars.select { |char| char =~ %r{[A-Z]} }
    end
  end

  # ------------
  #  Test cases
  # ------------

  describe Player do
    let(:player) { Player.new }

    describe "#add_weapon" do
      context "with \'a\'" do
        it "player has weapon \'a\'" do
          expect(player.has_weapon?('a')).to be_falsy
          player.add_weapon('a')
          expect(player.has_weapon?('a')).to be_truthy
        end
      end
    end
  end

  describe Exercise do
    context 'with \'gLDLBgBgHDaD\'' do
      let(:exercise) { Exercise.new('gLDLBgBgHDaD') }

      describe '#setting_weapons' do
        it 'player has weapons \'g\' and \'a\'' do
          exercise.send(:setting_weapons)
          player = exercise.instance_variable_get(:@player)
          expect(player.has_weapon?('g')).to be_truthy
          expect(player.has_weapon?('a')).to be_truthy
        end
      end

      describe '#setting_monsters' do
        it 'set monsters that has L, D, L, B, B, H, D, D' do
          exercise.send(:setting_monsters)
          monsters = exercise.instance_variable_get(:@monsters)
          expect(monsters[0].symbol).to eq 'L'
          expect(monsters[1].symbol).to eq 'D'
          expect(monsters[2].symbol).to eq 'L'
          expect(monsters[3].symbol).to eq 'B'
          expect(monsters[4].symbol).to eq 'B'
          expect(monsters[5].symbol).to eq 'H'
          expect(monsters[6].symbol).to eq 'D'
          expect(monsters[7].symbol).to eq 'D'
        end
      end

      describe '#extract_weapons' do
        it { expect(exercise.send(:extract_weapons)).to eq %w{g g g a} }
      end

      describe '#exctract_monsters' do
        it { expect(exercise.send(:extract_monsters)).to eq %w{L D L B B H D D} }
      end

      describe '#solve' do
        it { expect(exercise.solve).to eq 6 }
      end
    end

    context 'with \'DBcDLaLgDBH\'' do
      let(:exercise) { Exercise.new('DBcDLaLgDBH') }

      describe '#solve' do
        it { expect(exercise.solve).to eq 6 }
      end
    end

    context 'with \'JJca\'' do
      let(:exercise) { Exercise.new('JJca') }

      describe '#solve' do
        it { expect(exercise.solve).to eq 0 }
      end
    end

    context 'with \'FJDLBH\'' do
      let(:exercise) { Exercise.new('FJDLBH') }

      describe '#solve' do
        it { expect(exercise.solve).to eq 0 }
      end
    end

    context 'with \'HJBLFDg\'' do
      let(:exercise) { Exercise.new('HJBLFDg') }

      describe '#solve' do
        it { expect(exercise.solve).to eq 6 }
      end
    end

    context 'with \'HBaDLFJ\'' do
      let(:exercise) { Exercise.new('HBaDLFJ') }

      describe '#solve' do
        it { expect(exercise.solve).to eq 6 }
      end
    end

    context 'with \'DJaHLB\'' do
      let(:exercise) { Exercise.new('DJaHLB') }

      describe '#solve' do
        it { expect(exercise.solve).to eq 2 }
      end
    end

    context 'with \'gDLHJF\'' do
      let(:exercise) { Exercise.new('gDLHJF') }

      describe '#solve' do
        it { expect(exercise.solve).to eq 3 }
      end
    end

    context 'with \'cJFgLHD\'' do
      let(:exercise) { Exercise.new('cJFgLHD') }

      describe '#solve' do
        it { expect(exercise.solve).to eq 5 }
      end
    end

    context 'with \'FFBJaJJ\'' do
      let(:exercise) { Exercise.new('FFBJaJJ') }

      describe '#solve' do
        it { expect(exercise.solve).to eq 1 }
      end
    end
  end
end