[fix] Add heuristic to Python code.

connect_four.py

@@ -269,6 +269,57 @@ def log_game(games: list[dict], game_menu_mode: int, level: int, winner: int, mo
 
 # --- AI ---
 
+def evaluate_board(board: list[list[int]], ai_p: int, hu_p: int) -> int:
+    score = 0
+
+    # Center column bonus
+    for r in range(ROWS):
+        if board[3][r] == ai_p:
+            score += 3
+        elif board[3][r] == hu_p:
+            score -= 3
+
+    # Score a window of 4 cells by piece counts
+    def score_window(c: int, r: int, dc: int, dr: int) -> int:
+        ai, hu = 0, 0
+        for i in range(4):
+            v = board[c + i * dc][r + i * dr]
+            if v == ai_p:
+                ai += 1
+            elif v == hu_p:
+                hu += 1
+        if ai > 0 and hu > 0:
+            return 0
+        if ai == 3:
+            return 50
+        if ai == 2:
+            return 5
+        if hu == 3:
+            return -50
+        if hu == 2:
+            return -5
+        return 0
+
+    # Horizontal
+    for r in range(ROWS):
+        for c in range(COLS - 3):
+            score += score_window(c, r, 1, 0)
+    # Vertical
+    for r in range(ROWS - 3):
+        for c in range(COLS):
+            score += score_window(c, r, 0, 1)
+    # Diagonal up-right
+    for r in range(ROWS - 3):
+        for c in range(COLS - 3):
+            score += score_window(c, r, 1, 1)
+    # Diagonal down-right
+    for r in range(3, ROWS):
+        for c in range(COLS - 3):
+            score += score_window(c, r, 1, -1)
+
+    return score
+
+
 def minimax(
     board: list[list[int]], depth: int, alpha: int, beta: int,
     is_max: bool, ai_p: int, hu_p: int,
@@ -279,7 +330,7 @@ def minimax(
     if winner == hu_p:
         return -1000 - depth
     if depth == 0 or is_board_full(board):
-        return 0
+        return evaluate_board(board, ai_p, hu_p)
 
     best = -10000 if is_max else 10000
     for c in COL_ORDER:
@@ -309,7 +360,7 @@ def perform_ai_move(
     hu_p = 2 if ai_p == 1 else 1
     ply = demo_ply if is_demo else look_ahead
 
-    # Phase 1: instant win / block
+    # Phase 1a: check ALL columns for instant AI win
     for c in range(COLS):
         r = get_first_empty_row(board, c)
         if r != -1:
@@ -317,6 +368,12 @@ def perform_ai_move(
             if scan_board(board)[0] == ai_p:
                 board[c][r] = 0
                 return c
+            board[c][r] = 0
+
+    # Phase 1b: check ALL columns for opponent block
+    for c in range(COLS):
+        r = get_first_empty_row(board, c)
+        if r != -1:
             board[c][r] = hu_p
             if scan_board(board)[0] == hu_p:
                 board[c][r] = 0