def sortMoves(board, isWhite, movesMade):
moves = generateLegalMovesForColor(board, isWhite)
sortedMoves = []
for before, after, AIProm in moves:
move = (before, after, AIProm)
piece = board[before[0]][before[1]]
capturedPiece = board[after[0]][after[1]]
newBoard = deepcopy(board)
history = deepcopy(movesMade)
makeMove(newBoard, before, after, AIProm, history)
if board[before[0]][before[1]].upper != 'K':
if capturedPiece is not None:
if abs(pieceValue[capturedPiece]) > abs(pieceValue[piece]):
sortedMoves.insert(0, move)
continue
elif (after[0], after[1],
any(['Q', 'R', 'B', 'N', 'q', 'r', 'b', 'n',
None])) not in generateLegalMovesForColor(
newBoard, not isWhite):
sortedMoves.insert(0, move)
continue
else:
sortedMoves.insert(int(len(sortedMoves) / 2), move)
continue
if spotKing(board, not isWhite) in generateLegalMovesForColor(
newBoard, isWhite):
sortedMoves.insert(0, move)
continue
if (after[0], after[1],
any(['Q', 'R', 'B', 'N', 'q', 'r', 'b', 'n', None
])) in generateLegalMovesForColor(newBoard, not isWhite):
sortedMoves.insert(len(sortedMoves) - 1, move)
continue
sortedMoves.insert(int(len(sortedMoves) / 2), move)
return sortedMoves
def search(board, depth, isWhite, movesMade):
bestEval = float('-inf')
bestMove = None
legalMoves = generateLegalMovesForColor(board, isWhite)
for before, after, AIProm in legalMoves:
move = (before, after, AIProm)
newBoard = deepcopy(board)
history = deepcopy(movesMade)
makeMove(newBoard, before, after, AIProm, history)
value = -alphaBetaPruning(newBoard, depth - 1, not isWhite,
float('-inf'), float('inf'), history)
# value = -minimax(newBoard, depth-1, not isWhite, history)
if value >= bestEval:
bestEval = value
bestMove = move
return bestMove
def minimax(board, depth, isWhite, movesMade):
if depth == 0:
return evaluate(board, isWhite)
legalMoves = generateLegalMovesForColor(board, isWhite)
if len(legalMoves) == 0:
kingSquare = spotKing(board, isWhite)
if seeCheck(board, kingSquare, kingSquare, False):
return float('-inf')
return 0
bestEval = float('-inf')
for before, after, AIProm in legalMoves:
newBoard = deepcopy(board)
movesMade = deepcopy(movesMade)
makeMove(newBoard, before, after, AIProm, movesMade)
evaluation = -minimax(board, depth - 1, not isWhite, movesMade)
bestEval = max(evaluation, bestEval)
return bestEval
def alphaBetaPruning(board, depth, isWhite, alpha, beta, movesMade):
if depth == 0:
return evaluate(board, isWhite)
legalMoves = generateLegalMovesForColor(
board, isWhite) # Generates all legal moves this player can make
if len(legalMoves) == 0: # When the current player has no available moves
kingSquare = spotKing(board, isWhite)
if seeCheck(board, kingSquare, kingSquare, False):
return float(
'-inf') # Returns negative infinity if the player is in check
return 0
for before, after, AIProm in legalMoves:
newBoard = deepcopy(board)
history = deepcopy(movesMade)
makeMove(newBoard, before, after, AIProm, history)
evaluation = -alphaBetaPruning(board, depth - 1, not isWhite, -beta,
-alpha, history)
if evaluation >= beta:
return beta
alpha = max(alpha, evaluation)
return alpha
def makeRandomMove(board, isWhite):
legalMoves = generateLegalMovesForColor(board, isWhite)
move = random.choice(legalMoves)
return move