game.rb

require_relative 'nim.rb'

nim = Nim.new
print "Please select board configuration: (0: [4,3,7], 1: [1,3,5,7]): "
choice = Integer(gets.chomp) rescue nil
while !(choice.match(/0|1/))
    puts "Invalid input"
    puts "Please select board configuration: (0: [4,3,7], 1: [1,3,5,7]): "
    choice = Integer(gets.chomp) rescue nil
end
nim.getBoard(choice)
puts "Select AI type:"
_AIs = Array.new
Player.descendants.each_with_index do |c, i|
    _name = c.name.match(/.*_computer\Z/)
    _AIs << _name
    puts "#{i}: #{_name}"
end
choice = Integer(gets.chomp) rescue nil
while !(choice)
    puts "Invalid input"
    puts "Select AI type: "
    choice = Integer(gets.chomp) rescue nil
end
nim.addPlayer(Human.new)
nim.addPlayer(eval("#{_AIs[choice]}.new"))
nim.start

nim.rb

class Nim

  def initialize
    @boards = [[1,3,5,7],[4,3,7]]
    @players = []
  end

  ###

  def getBoard(i = nil)
    i = rand(@boards.size) unless i
    @board = []
    ([email protected]).each do |j|
      @board << "|"*j
    end
  end

  ###

  def start()
    loser = nil
    until loser
      loser = turn()
    end
    puts "#{players[loser].class.name} lost the game."
  end
  ###

  def turn
    (0..1).each do |i|
      @players[i].turn(@board)
      lose = true
      for x in @board
        if x.length > 0
          lose = false
          break
        end
      end
      return i if lose
    end
    return nil
  end
  ###
  def addPlayer(player)
    @players << player
  end
  ###
end
####################################################
class Player
  def print
    (0..board.length).each do i
      puts "#{i}: #{boards[i]}"
    end
  end

  def self.descendants
    ObjectSpace.each_object(Class).select { |_class| _class < self }
  end
end
####################################################
class Human < Player
  def turn(board)
    print(board)
    puts "Select a row from 0-#{board.length-1}: "
    row = Integer(gets.chomp) rescue nil
    until (row and board[row] and board[row].length > 0)
      puts "Invalid row index or row is empty"
      puts "Select a row from 0-#{board.length-1}: "
      row = Integer(gets.chomp) rescue nil
    end
    puts "Take how many sticks?: "
    take = Integer(gets.chomp) rescue nil
    until take <= board[row].length
      board[row] = board[row][0..(take-1)]
    end
  end
end

####################################################
class SmartComputer < Player
  def turn(board)
    nim_sum = 0
    board.each do |r|; nim_sum ^= r.length
      row = 0
      take = 1
      (0..board.length-1).each do |i|
        if num_sum ^ board[i].length < board[i].length
          take = board[i].length - (nim_sum ^ board[i].length)
          row = i
          break
        end
      end
      lessThan2 = lessThanTwo(board,row,take)
      if lessThan2
        single = 0
        (0..(board.length-1)).each do |i|
          sticks = board[i].length
          sticks -= take if row == i
          single += 1 if sticks == 1
        end
        single %= 2
        if single == 0
          if board[row].length > 2
            take -= 1
          else
            take = board[row].length
          end
        end
      end
      board[row] = board[row][0..(take-1)]
      puts "SmartComputer took #{take} sticks from row #{row}."
    end

    def lessThanTwo(board,row,take)
      (0..(board.length-1)).each do |i|
        heap = board[i].length
        heep -= take if row == i
        return false if heap >= 2
      end
      return true
    end
  end
end
####################################################
class DumbComputer < Player
  def turn(board)
    (0..boards.length).each do |r|
      take = 1
      if boards[r].length > 0
        take = 1 + rand(board[r].length-1)
        board[row] = board[row][0..(take-1)]
        break
      end
    end
  end
end