add method to check replay for last feasible state (binary search)

check_game.py

@@ -0,0 +1,70 @@
+import copy
+from typing import Tuple, Optional
+
+from database import conn
+from compress import decompress_deck, decompress_actions, compress_actions, link
+from hanabi import Action, HanabiInstance, GameState
+from sat import solve_sat
+from download_data import export_game
+
+
+# returns number of first turn before which the game was infeasible (counting from 0)
+# and a replay achieving maximum score (from this turn onwards) if instance is feasible
+# 0 if instance is infeasible
+# 1 if instance is feasible but first turn is suboptimal
+# ...
+# (number of turns) if replay was winning
+def check_game(game_id: int) -> Tuple[int, GameState]:
+    with conn.cursor() as cur:
+        cur.execute("SELECT games.num_players, deck, actions, score, games.variant_id FROM games "
+                    "INNER JOIN seeds ON seeds.seed = games.seed "
+                    "WHERE games.id = (%s)",
+                    (game_id,)
+                    )
+        (num_players, compressed_deck, compressed_actions, score, variant_id) = cur.fetchone()
+        deck = decompress_deck(compressed_deck)
+        actions = decompress_actions(compressed_actions)
+
+        instance = HanabiInstance(deck, num_players, variant_id=variant_id)
+
+        if instance.max_score == score:
+            # instance has been won, nothing to compute here
+            return len(actions)
+        
+        # store the turn numbers *before* we know the game was (in)feasible
+        solvable_turn = 0
+        unsolvable_turn = len(actions)
+
+        # first, check if the instance itself is feasible:
+        game = GameState(instance)
+        solvable, solution = solve_sat(game)
+        if not solvable:
+            return -1, solution
+
+        while (unsolvable_turn - solvable_turn > 1):
+            try_turn = (unsolvable_turn + solvable_turn) // 2
+            try_game = copy.deepcopy(game)
+            assert(len(try_game.actions) == solvable_turn)
+            for a in range(solvable_turn, try_turn):
+                try_game.make_action(actions[a])
+            solvable, potential_sol = solve_sat(try_game)
+            if solvable:
+                solution = potential_sol
+                game = try_game
+                solvable_turn = try_turn
+            else:
+                unsolvable_turn = try_turn
+
+        assert(unsolvable_turn - 1 == solvable_turn)
+        return unsolvable_turn, solution
+
+if __name__ == "__main__":
+    game_id = 961092
+    export_game(game_id)
+    print("checking game {}".format(game_id))
+    turn, sol = check_game(game_id)
+    if turn != 0:
+        print(turn, link(sol))
+    else:
+        print("instance is unfeasible")
+    pass