2024

README.md

 You can run the binder directly by clicking here
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module_example.py

+x = 1024
+y = 2048
+
+print("Hello from a module!")
+
+print(__name__)

tic-tac-toe.py

+def new_board():
+	"""Create a tuple representing a tic-tac-toe board:
+	- first element is the current player (0 or 1)
+	- the other elements are three tuple representing the rows of the grid (which elements are 0 or 1 or None)
+	"""
+	return (0,
+		(None,) * 3,
+		(None,) * 3,
+		(None,) * 3,
+	)
+
+
+def move(board, row_index, column_index):
+	"""Create a new board where the current player has moved in the given position (zero-indexed) and the current player is updated.
+	"""
+	player, *grid = board
+	try:
+		row = grid[row_index]
+		if row[column_index] is not None:
+			raise ValueError
+	except IndexError:
+		raise ValueError("Illegal move: the position is not on the grid")
+	except ValueError:
+		raise ValueError("Illegal move: the cell is not empty")
+	new_row = (player if j == column_index else x for j, x in enumerate(row))
+	grid[row_index] = tuple(new_row)
+	new_player = 1 - player
+	return new_player, *grid
+
+
+def legal_moves(board):
+	"""Return a list of the free positions on the board if nobody has won, else an empty list.
+	"""
+	if winner(board) is not None:
+		return []
+	return [(i,j)
+		for i, row in enumerate(board[1:])
+		for j, x in enumerate(row)
+		if x is None
+	]
+
+
+configurations = (
+	tuple((i, i) for i in range(3)),
+	tuple((i, 2-i) for i in range(3)),
+	*(tuple((i, j) for j in range(3)) for i in range(3)),
+	*(tuple((j, i) for j in range(3)) for i in range(3))
+)
+
+def winner(board):
+	"""Return the winning player if somebody won else None.
+	"""
+	grid = board[1:]
+	for player in range(2):
+		if any(
+			all(grid[i][j] == player for i, j in c)
+			for c in configurations
+		):
+			return player
+	return None
+
+
+def engine(board, fuel = 1, memory = ({}, {}, {}), verbose = False):
+	"""Simulate all moves from this position (iterating one time for each unit of fuel) and update memory.
+	Return:
+	- a winnig move if one is known
+	- else a move not known, if any
+	- else a move known to give a drawing game to the opponent, if any
+	- else the first available move, if any
+	- else None
+	"""
+
+	# is this a known position?
+	for d in memory:
+		if board in d:
+			return d[board]
+
+	moves = legal_moves(board)
+	if verbose: print(f"\t{moves = }")
+
+	# this is a final position
+	if not moves:
+		winning_player = winner(board)
+		index = 2 if winning_player is None else winning_player
+		memory[index][board] = None
+		return None
+
+	# memorize in depth analisys
+	if fuel:
+		for i, j in moves:
+			new_board = move(board, i, j)
+			engine(new_board, fuel - 1, memory)
+
+	# choose next move
+	player = board[0]
+	draw, unknown = None, None
+	for m in reversed(moves):
+		i, j = m
+		new_board = move(board, i, j)
+		if new_board in memory[player]:
+			if verbose: print(f"\t{m} wins")
+			memory[player][board] = m
+			return m
+		if new_board in memory[1 - player]:
+			if verbose: print(f"\t{m} loses")
+			continue
+		if new_board in memory[2]:
+			if verbose: print(f"\t{m} draws, set")
+			draw = m
+			continue
+		if verbose: print(f"\t{m} unknown, set")
+		unknown = m
+	if unknown is None:
+		if draw is None:
+			memory[1 - player][board] = moves[0]
+			return moves[0]
+		memory[2][board] = draw
+		return draw
+	return unknown
+
+
+player_symbol = {0: 'X', 1: 'O', None: ' '}
+
+def print_board(board):
+	player, *grid = board
+	print(player_symbol[player], "to move:")
+	lines = [f' {" | ".join(player_symbol[x] for x in row)} ' for row in grid]
+	print("\n---+---+---\n".join(lines))
+	print()
+
+
+def game(player_names, board = None, verbose = None):
+	board = new_board() if board is None else board
+	print_board(board) if verbose is not False else print('.', end = '')
+	while True:
+		player = board[0]
+		name = player_names[player]
+		m = engine(board, 2, verbose = verbose)
+		if m is None:
+			print()
+			return
+		board = move(board, *m)
+		print_board(board) if verbose is not False else print('.', end = '')