Ruby实现类Mastermind游戏时线索提示逻辑异常求助

问题现象 #

开发类Mastermind猜数字游戏时，基础输入接收、合法性校验、游戏流程控制均可正常运行，但线索提示模块存在两类异常：

• 「数字正确且位置正确」的提示完全无法按规则生效
• 「数字正确但位置错误」的提示计数不稳定，某轮猜测匹配到对应数字后，后续轮次即使输入包含相同数字，该类提示的计数也会异常消失

原始问题代码 #

class Mastermind
  def initialize
    @answer = create_code
    @guess_number = 12
    @winner = false
  end

  def ask_what_you_guess
    while @guess_number > 0 do
      break if @winner
      p "#{@guess_number.to_s.rjust(2)} attempts left: "
      input = gets.chomp.split("")
      if guess_is_vaild?(input)
        win = guess(input)
      else
        puts "Invalid input! Please try again!"
      end
    end
    
    game_over
  end

  def guess(number)
    if number == @answer
      @winner = true
    else
      x = get_x(number)
      y = get_y(number)
      puts "Please try again, #{x} Correct/#{y} Wrong Spot."
      @guess_number -= 1
    end
  end

  def game_over
    input = nil
    until ["y", "n"].include?(input)
      if @winner
        print "You won! Would you like to try again? [Y/N]"
      else
        print "You lose, this time!  Would you like to give it another try? [Y/N]"
      end
      input = gets.chomp.downcase
    end
    restart_game?(input)
  end

  def restart_game?(input)
    case input
    when "y"
      true
    when "n"
      false
    end
  end

  def create_code
    code = []
    until code.size == 4 do
      number = (rand(6) + 1).to_s
      code << number unless code.include?(number)
    end
    code
  end

  def guess_is_vaild?(input)
    if input.size == 4 && input.all? { |e| "123456".include? (e) }
      return true
    else
      return false
    end
  end

  def get_y(number)
    y = 0 
    number.each_with_index do |e, i|
      y += 1 if e == @answer[i]
    end
    return y 
  end

  def get_x(number)
    x = 0
    number.each_with_index do |e, i|
      x += 1 if e != number[i] && number.include?(e)
    end
    return x 
  end
end

puts "***********************************************\n" \
     "*CodeBreaker: can you guess the right number? *\n" \
     "*   Guess a 4 digit number composed of 1-6.   *\n" \
     "*    Y means how many numbers are correct.    *\n" \
     "*    X correct but in the wrong position.     *\n" \
     "***********************************************"

restart = true
while restart do
  mastermind = Mastermind.new
  restart = mastermind.ask_what_you_guess
end
puts "Thanks for playing CodeBreaker, Code Master!"

根因定位 #

代码存在3处核心逻辑错误，直接导致线索提示异常：

1. 变量映射颠倒：get_y方法实际实现的是「数字+位置均正确」的计数逻辑，但输出提示时将x标记为Correct、y标记为Wrong Spot，对应关系完全错位。
2. 比对对象错误：get_x方法判断位置是否匹配时，错误地将当前遍历元素和猜测数组自身的同位置元素比较（e != number[i]是恒假判断），根本没有和标准答案数组@answer做比对，计数逻辑从根本上失效。
3. 无去重计数逻辑：原逻辑没有排除已经判定为「位置正确」的数字，也没有处理数字重复出现的计数边界，导致出现重复计数、跨轮次计数异常的不稳定问题。

修复方案 #

按照Mastermind标准规则重写线索计数逻辑，遵循「先统计精确匹配，再统计部分匹配，重复数字不重复计数」的原则：

1. 逐位比对猜测值和答案，先统计「数字和位置都正确」的精确匹配数量，标记这些已匹配的位置，后续统计时排除这部分数字
2. 对剩余未匹配的猜测数字、答案数字分别统计出现频率
3. 对两边共有的数字，取两边剩余出现次数的最小值累加，得到「数字正确但位置错误」的部分匹配数量，避免重复计数

替换原有get_x、get_y方法，同时修正guess方法中的输出对应关系，修复后的核心代码如下：

def guess(number)
  if number == @answer
    @winner = true
  else
    exact, partial = get_exact_and_partial(number)
    puts "Please try again, #{exact} Correct (right number and position)/#{partial} Wrong Spot (right number, wrong position)."
    @guess_number -= 1
  end
end

def get_exact_and_partial(number)
  exact = 0
  matched_guess = Array.new(4, false)
  matched_answer = Array.new(4, false)

  # 先统计精确匹配
  4.times do |i|
    if number[i] == @answer[i]
      exact += 1
      matched_guess[i] = true
      matched_answer[i] = true
    end
  end

  # 统计剩余未匹配数字的频率
  guess_remaining = Hash.new(0)
  answer_remaining = Hash.new(0)
  4.times do |i|
    guess_remaining[number[i]] += 1 unless matched_guess[i]
    answer_remaining[@answer[i]] += 1 unless matched_answer[i]
  end

  # 统计部分匹配
  partial = 0
  guess_remaining.each do |num, count|
    partial += [count, answer_remaining[num]].min
  end

  [exact, partial]
end

替换后删除原有失效的get_x、get_y方法即可，线索计数将完全符合游戏规则，不会再出现计数异常问题。

内容的提问来源于stack exchange，提问作者C-Lund2021