add function determine_winner_four_of_a_kind to fix bug in determine_…

…winner for four of a kind tie break

Former-commit-id: 4595122

rlcard/games/limitholdem/utils.py

@@ -506,6 +506,33 @@ def determine_winner(key_index, hands, all_players, potential_winner_index):
         count+=1
     return all_players
 
+def determine_winner_four_of_a_kind(hands, all_players, potential_winner_index):
+    '''
+    Find out who wins in the situation of having players which all have a four of a kind
+    Args:
+        key_index(int): the position of a card in a sorted handcard
+        hands(list): cards of those players with a four of a kind
+        e.g. hands = [['CT', 'ST', 'H9', 'B9', 'C2', 'C8', 'C7'], ['CJ', 'SJ', 'H9', 'B9', 'C2', 'C8', 'C7'], ['CT', 'ST', 'H9', 'B9', 'C2', 'C8', 'C7']]
+        all_players(list): all the players in this round, 0 for losing and 1 for winning or draw
+        potential_winner_index(list): the positions of those players with same highest hand_catagory in all_players
+    Returns:
+        [0, 1, 0]: player1 wins
+        [1, 0, 0]: player0 wins
+        [1, 1, 1]: draw
+        [1, 1, 0]: player1 and player0 draws
+
+    '''
+    ranks = []
+    for hand in hands:
+        rank_1 = hand.STRING_TO_RANK[hand.best_five[-1][1]]  # rank of the four of a kind
+        rank_2 = hand.STRING_TO_RANK[hand.best_five[0][1]]  # rank of the kicker
+        ranks.append((rank_1, rank_2))
+    max_rank = max(ranks)
+    for i, rank in enumerate(ranks):
+        if rank == max_rank:
+            all_players[potential_winner_index[i]] = 1
+    return all_players
+
 def compare_hands(hands):
     '''
     Compare all palyer's all seven cards
@@ -579,7 +606,7 @@ def final_compare(hands, potential_winner_index, all_players):
         for _ in potential_winner_index:
             equal_hands.append(hands[_])
         if hands[potential_winner_index[0]].category == 9 or hands[potential_winner_index[0]].category == 5 or hands[potential_winner_index[0]].category == 8:
-            return determine_winner([0], equal_hands, all_players, potential_winner_index)
+            return determine_winner_four_of_a_kind(equal_hands, all_players, potential_winner_index)
         if hands[potential_winner_index[0]].category == 7:
             return determine_winner([2, 0], equal_hands, all_players, potential_winner_index)
         if hands[potential_winner_index[0]].category == 4:

tests/utils/test_holdem_utils.py

@@ -253,6 +253,12 @@ def test_compare_hands(self):
                                 ['H2', 'H3', 'C4', 'D5', 'CQ', 'SK', 'SA']])  # straight beginning with A
         self.assertEqual(winner, [0, 1])
 
+        winner = compare_hands([['S2', 'D8', 'H8', 'S7', 'S8', 'C8', 'D3'],  # 8-four of a kind, kicker 7
+                                ['S2', 'D8', 'H8', 'S9', 'S8', 'C8', 'D3'],  # 8-four of a kind, kicker 9
+                                ['H3', 'C3', 'HT', 'S3', 'ST', 'CT', 'D3'],  # 3-four of a kind, kicker T
+                                ])
+        self.assertEqual(winner, [0, 1, 0])
+
 
 if __name__ == '__main__':
     unittest.main()