def min_value(board, a, b):
""" Returns the minimum value for thr board.
"""
# initialize v = +infinity
v = 1000000
# Check state
result = common.game_status(board)
# Check results
if result == common.constants.X:
return 1
elif result == common.constants.O:
return -1
elif check_tie(board):
return 0
# If game is not finished - check the value of v
for y in range(TICTACTOE_HEIGHT):
for x in range(TICTACTOE_WIDTH):
if common.get_cell(board, y, x) == common.constants.NONE:
new_board = board[:]
common.set_cell(new_board, y, x, common.constants.O)
v = min(v, max_value(new_board, a, b))
# For abprun_tictactoe()
if (a is not None) and (b is not None):
if v <= a:
return v
b = min(b, v)
return v
def abminval(board, turn, a, b):
val = 2 # has to be less than owin
# check whose turn it is...
if turn == common.constants.O:
next_ = common.constants.X
else:
next_ = common.constants.O
# Check if the game is already finished or not...
gstat = common.game_status(board)
if gstat == common.constants.O:
val = -1
elif gstat == common.constants.X:
val = 1
elif common.constants.NONE not in board:
val = 0
else:
for i in range(3):
for j in range(3):
cval = common.get_cell(board, i, j)
if cval == common.constants.NONE:
newboard = board[:]
common.set_cell(newboard, i, j, turn)
val = min(val, abmaxval(newboard, next_, a, b))
if val <= a:
return val
b = min(val, b)
return val
def min_val(board):
v = common.constants.X
for i in range(0, 3):
for j in range(0, 3):
if common.get_cell(board, i, j) == common.constants.NONE:
common.set_cell(board, i, j, common.constants.O)
v = min(v, minmax_tictactoe(board, common.constants.X))
common.set_cell(board, i, j, common.constants.NONE)
return v
def min_val_ABPrun(board, alpha, beta):
v = common.constants.X
for i in range(0, 3):
for j in range(0, 3):
if common.get_cell(board, i, j) == common.constants.NONE:
common.set_cell(board, i, j, common.constants.O)
v = min(
v,
abprun_tictactoe_helper(board, common.constants.X, alpha,
beta))
common.set_cell(board, i, j, common.constants.NONE)
if v == min(v, alpha):
return v
beta = min(beta, v)
return v
