ass3: finish bucket_game

assignment3/bucket_game.py

@@ -1,3 +1,5 @@
+import typing
+
 State = tuple[int, list[str | int]]  # Tuple of player (whose turn it is),
 # and the buckets (as str)
 # or the number in a bucket
@@ -42,3 +44,44 @@ class Game:
             print(f"P1's utility is {self.utility(state, 0)}")
         else:
             print(f"it is P{self.to_move(state)+1}'s turn")
+
+
+def minimax_search(game: Game, state: State) -> Action | None:
+    _, result = max_value(game, state)
+    return result
+
+
+def max_value(game: Game, state: State) -> tuple[float, Action | None]:
+    if game.is_terminal(state):
+        return game.utility(state, player), None
+    v, move = float("-inf"), float("-inf")
+    for a in game.actions(state):
+        v2, a2 = min_value(game, game.result(state, a))
+        if v2 > v:
+            v, move = v2, a
+    return typing.cast(float, v), typing.cast(Action, move)
+
+
+def min_value(game: Game, state: State) -> tuple[float, Action | None]:
+    if game.is_terminal(state):
+        return game.utility(state, player), None
+    v, move = float("+inf"), float("+inf")
+    for a in game.actions(state):
+        v2, a2 = max_value(game, game.result(state, a))
+        if v2 < v:
+            v, move = v2, a
+    return typing.cast(float, v), typing.cast(Action, move)
+
+
+game = Game()
+
+state = game.initial_state()
+game.print(state)
+while not game.is_terminal(state):
+    player = game.to_move(state)
+    action = minimax_search(game, state)  # The player whose turn it is
+    # is the MAX player
+    print(f"P{player+1}'s action: {action}")
+    assert action is not None
+    state = game.result(state, action)
+    game.print(state)