63 lines
1.4 KiB
Python
63 lines
1.4 KiB
Python
__all__ = ["PLAYER1", "PLAYER2", "Connect4"]
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PLAYER1, PLAYER2 = "red", "yellow"
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class Connect4:
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"""
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A Connect Four game.
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Play moves with :meth:`play`.
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Get past moves with :attr:`moves`.
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Check for a victory with :attr:`winner`.
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"""
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def __init__(self):
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self.moves = []
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self.top = [0 for _ in range(7)]
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self.winner = None
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@property
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def last_player(self):
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"""
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Player who played the last move.
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"""
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return PLAYER1 if len(self.moves) % 2 else PLAYER2
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@property
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def last_player_won(self):
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"""
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Whether the last move is winning.
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"""
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b = sum(1 << (8 * column + row) for _, column, row in self.moves[::-2])
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return any(b & b >> v & b >> 2 * v & b >> 3 * v for v in [1, 7, 8, 9])
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def play(self, player, column):
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"""
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Play a move in a column.
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Returns the row where the checker lands.
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Raises :exc:`RuntimeError` if the move is illegal.
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"""
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if player == self.last_player:
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raise RuntimeError("It isn't your turn.")
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row = self.top[column]
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if row == 6:
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raise RuntimeError("This slot is full.")
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self.moves.append((player, column, row))
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self.top[column] += 1
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if self.winner is None and self.last_player_won:
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self.winner = self.last_player
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return row
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