class Brain(object):
"""This is our min max guy"""
def __init__(self, scratch_board, token):
self.scratch_board = scratch_board
self.scratch_judge = Judge(self.scratch_board)
self.opponent = { 'O':'X', 'X':'O' }
self.token = token
self.best_move = None
def evaluateMove(self, p=None, board=None, depth=10):
"""Do the min max evaluation"""
if board is None:
board = [' '] * 9
depth += 1
scores = []
moves = []
#First off are we at the endgame state?
#if ' ' not in board: #The board is full the game must be done.
self.scratch_judge.board.tokens = board
winner, state = self.scratch_judge.evalGame()
if winner is None and state == 'done':
return 0
elif winner == self.token:
return 10 + depth
elif winner == self.opponent[self.token]:
return 10 - depth
#winner and state are both None
#Now we build up our moves
for next_move in self.scratch_judge.board.getPossibleMoves():
#do the move
self.scratch_judge.board.addToken(p, next_move)
#get the new game state
new_board = self.scratch_judge.board.getBoard()
#re-evaluate
score = self.evaluateMove(p=self.opponent[p], board=new_board, depth=depth)
scores.append(score)
moves.append(next_move)
self.scratch_judge.board.tokens[next_move] = ' '
#now fix the messed up min max that cannot work.
if p == self.token: #Calc the max.
max_score = max(scores)
idx = scores.index(max_score)
self.best_move = moves[idx]
return scores[idx]
else: #Calc the min
min_score = min(scores)
idx = scores.index(min_score)
self.best_move = moves[idx]
return scores[idx]
class Board(object):
def __init__(self, player=None, computer=None):
"""
:rtype: object
"""
self.tokens = [' '] * 9
self.player_token = player
self.computer_token = computer
self.judge = Judge(self)
def playAgain(self):
"""Find out if we want another go"""
print('Do you want to play again? (yes or no)')
return self._raw_input().lower().startswith('y')
def isWinner(self):
"""Did a win just happen?"""
result = self.judge.evalGame()
if result[0] is not None:
return 'win'
elif result == [None, None]:
return False
else:
return 'draw'
def makeComputerMove(self, brain):
"""Make the computer's move"""
results = []
tokens = copy.copy(self.tokens)
if self.take_center():
best = 4
else:
brain.evaluateMove(p=self.computer_token, board=tokens)
best = brain.best_move
self.addToken(self.computer_token, int(best))
print(self.drawBoard())
def take_center(self):
"""figure out if we can have the center square
rather than calculating the whole tree our first
move"""
token_count = self.tokens.count(' ')
if token_count == 9:
return True
elif token_count == 8 and self.tokens[4] == ' ':
return True
return False
def getPlayerMove(self):
"""Get the player's move"""
move = ' '
while move not in self.getPossibleMoves():
print('What is your next move? (1-9)')
move = self._raw_input()
try:
int(move)
except:
print("Please enter a digit")
print(self.drawBoard())
continue
try:
self.addToken(self.player_token, int(move) - 1)#make the move into an index of the board
print(self.drawBoard())
break
except TokenPlacementException:
print("please select an empty spot")
print(self.drawBoard())
def firstMove(self):
"""Computer goes first"""
which = random.randint(1, 2)
if which == 1:
return 'computer'
else:
return 'player'
def drawBoard(self):
"""Draw a tic-tac-toe board"""
b = '\n\n%s|%s|%s\n' % tuple(self.tokens[:3])
b += '_____\n'
b += '%s|%s|%s\n' % tuple(self.tokens[3:6])
b += '_____\n'
b += '%s|%s|%s\n\n' % tuple(self.tokens[6:])
return b
def addToken(self, token, idx):
"""Add a token to the board or raise an exception
str token "x" or "o"
int idx 0-8"""
idx = int(idx)
if idx > 8 or idx < 0:
msg = "Invalid index %s " % idx
raise TokenPlacementException(msg)
if self.tokens[idx] == ' ':
self.tokens[idx] = token
else:
msg = "Token at %s" % idx
raise TokenPlacementException(msg)
def getBoard(self):
return copy.copy(self.tokens)
def getPossibleMoves(self):
"""Return the indexes of possible moves"""
result = list()
for i in range(9):
if self.tokens[i] == ' ':
result.append(i)
return result
def inputPlayerLetter(self):
"""Allow the player to choose a letter"""
letter = ''
while not (letter == 'X' or letter == 'O'):
print('Do you want to be X or O?')
letter = self._raw_input()
letter = letter.upper()
if letter == 'X':
self.player_token = letter
self.computer_token = 'O'
break
elif letter == 'O':
self.player_token = letter
self.computer_token = 'X'
break
def _raw_input(self):
return input()
