From a55714f35ea866647e4c3d967d890aaf14312f9b Mon Sep 17 00:00:00 2001
From: fredrikr79 <fredrikrobertsen7@gmail.com>
Date: Tue, 21 Oct 2025 13:57:03 +0200
Subject: [PATCH] ass3: init tic_tac_toe

---
 assignment3/tic_tac_toe.py | 78 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 assignment3/tic_tac_toe.py

diff --git a/assignment3/tic_tac_toe.py b/assignment3/tic_tac_toe.py
new file mode 100644
index 0000000..d07fb5f
--- /dev/null
+++ b/assignment3/tic_tac_toe.py
@@ -0,0 +1,78 @@
+from copy import deepcopy
+
+State = tuple[int, list[list[int | None]]]  # Tuple of player (whose turn it is),
+# and board
+Action = tuple[int, int]  # Where to place the player's piece
+
+
+class Game:
+    def initial_state(self) -> State:
+        return (0, [[None, None, None], [None, None, None], [None, None, None]])
+
+    def to_move(self, state: State) -> int:
+        player_index, _ = state
+        return player_index
+
+    def actions(self, state: State) -> list[Action]:
+        _, board = state
+        actions = []
+        for row in range(3):
+            for col in range(3):
+                if board[row][col] is None:
+                    actions.append((row, col))
+        return actions
+
+    def result(self, state: State, action: Action) -> State:
+        _, board = state
+        row, col = action
+        next_board = deepcopy(board)
+        next_board[row][col] = self.to_move(state)
+        return (self.to_move(state) + 1) % 2, next_board
+
+    def is_winner(self, state: State, player: int) -> bool:
+        _, board = state
+        for row in range(3):
+            if all(board[row][col] == player for col in range(3)):
+                return True
+        for col in range(3):
+            if all(board[row][col] == player for row in range(3)):
+                return True
+        if all(board[i][i] == player for i in range(3)):
+            return True
+        return all(board[i][2 - i] == player for i in range(3))
+
+    def is_terminal(self, state: State) -> bool:
+        _, board = state
+        if self.is_winner(state, (self.to_move(state) + 1) % 2):
+            return True
+        return all(board[row][col] is not None for row in range(3) for col in range(3))
+
+    def utility(self, state, player):
+        assert self.is_terminal(state)
+        if self.is_winner(state, player):
+            return 1
+        if self.is_winner(state, (player + 1) % 2):
+            return -1
+        return 0
+
+    def print(self, state: State):
+        _, board = state
+        print()
+        for row in range(3):
+            cells = [
+                " " if board[row][col] is None else "x" if board[row][col] == 0 else "o"
+                for col in range(3)
+            ]
+            print(f" {cells[0]} | {cells[1]} | {cells[2]}")
+            if row < 2:
+                print("---+---+---")
+        print()
+        if self.is_terminal(state):
+            if self.utility(state, 0) > 0:
+                print(f"P1 won")
+            elif self.utility(state, 1) > 0:
+                print(f"P2 won")
+            else:
+                print("The game is a draw")
+        else:
+            print(f"It is P{self.to_move(state)+1}'s turn to move")