Class: TTT::Minimax

Inherits:
Object
  • Object
show all
Defined in:
lib/games/tictactoe/minimax.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(board, number_of_turns_taken, human_value, computer_value) ⇒ Minimax

Returns a new instance of Minimax.



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# File 'lib/games/tictactoe/minimax.rb', line 7

def initialize(board, number_of_turns_taken, human_value, computer_value)
  @board = board
  @number_of_turns_taken = number_of_turns_taken
  @human_value = human_value
  @computer_value = computer_value
end

Instance Attribute Details

#board ⇒ Object

Returns the value of attribute board.



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# File 'lib/games/tictactoe/minimax.rb', line 5

def board
  @board
end

#choice ⇒ Object

Returns the value of attribute choice.



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# File 'lib/games/tictactoe/minimax.rb', line 5

def choice
  @choice
end

#computer_value ⇒ Object

Returns the value of attribute computer_value.



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# File 'lib/games/tictactoe/minimax.rb', line 5

def computer_value
  @computer_value
end

#human_value ⇒ Object

Returns the value of attribute human_value.



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# File 'lib/games/tictactoe/minimax.rb', line 5

def human_value
  @human_value
end

#number_of_turns_taken ⇒ Object

Returns the value of attribute number_of_turns_taken.



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# File 'lib/games/tictactoe/minimax.rb', line 5

def number_of_turns_taken
  @number_of_turns_taken
end

Instance Method Details

#run_minimax ⇒ Object 



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# File 'lib/games/tictactoe/minimax.rb', line 14

def run_minimax
  scores = []
  choices = []

  board_won = board.won?
  board_full = board.full?

  if board_won || board_full
    #rewind one player to see which player took last turn and therefore won the game
    self.number_of_turns_taken -= 1
    return score(board_won)
  end

  # @logger.debug "avaliable choices collection: #{available_choices}"

  available_choices.each do |available_choice|
    board_copy = Marshal.load(Marshal.dump(board))
    board_copy.change_square(available_choice, player_value)
    choices.push(available_choice)
    minimax = TTT::Minimax.new(board_copy, number_of_turns_taken + 1, human_value, computer_value)
    scores.push minimax.run_minimax
  end

  if computer_current_player?
    #https://stackoverflow.com/questions/2149802/in-ruby-what-is-the-cleanest-way-of-obtaining-the-index-of-the-largest-value-in
    max_score_index = scores.each_with_index.max[1]
    self.choice = choices[max_score_index]
    return scores[max_score_index]
  else
    # This is the min calculation
    min_score_index = scores.each_with_index.min[1]
    self.choice = choices[min_score_index]
    return scores[min_score_index]
  end
end