ass3: implement minimax_search

assignment3/halving_game.py

@@ -47,8 +47,30 @@ class Game:
 
 
 def minimax_search(game: Game, state: State) -> Action | None:
-    # YOUR CODE HERE
+    _, result = max_value(game, state)
-    assert False, "Not implemented"
+    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 float(v), 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 float(v), Action(move)
 
 
 game = Game(5)