如何在Haskell中创建函数minimax？

我一直在努力在Haskell中创建minimax函数，但找不到任何更好的替代方法，因此我问：

我想创建以下函数：

minimax :: Player -> Rose Board -> Rose Int

我想得到一个由整数组成的玫瑰树，这些整数必须是1，0或-1（一个动作对轮到的玩家来说可以是好的，中性的，也可以是坏的）

(root :> leaves)               -- constructor of a Rose
(board :> boards)              -- constructor of a Rose Board
(Int :> Ints)                  -- constructor of a Rose Int

我编写了hasWinner、minimum和maximum函数，使事情变得更简单：

hasWinner :: Board -> Maybe Player

minimum' :: [Int] -> Int
minimum' (x:xs) | x == -1 = -1
                | otherwise = minimum' xs

maximum' :: [Int] -> Int
maximum' (x:xs) | x == 1 = 1
                | otherwise = maximum' xs

此外，我认为我的基本情况如下：

minimax player (board :> []) = (0 :> [])

minimax :: Player -> Rose Board -> Rose Int
minimax p (r :> [])   | hasWinner r == Just P1 = 1    :> []
                      | hasWinner r == Just P2 = (-1) :> []
                      | otherwise              = 0    :> []
minimax P1 (r :> rs) = maximum (map root xs) :> xs
    where xs = map (minimax (nextPlayer P1)) rs

minimax P2 (r :> rs) = minimum (map root xs) :> xs
    where xs = map (minimax (nextPlayer P2)) rs

目前我正处于这样的境地：

minimax player (board :> boards)| maximum' [(isWinner player b (minimax' player)) | (b :> bs) <- boards] == 1 = _
                                | minimum' [(isWinner player b (minimax' player)) | (b :> bs) <- boards] == -1 = _
                                | otherwise = _
                 where   minimax' player     | player == P1 = P2
                                             | otherwise = P1
                         isWinner p1 board p2    | hasWinner board == Just p1 = 1
                                                 | hasWinner board == Just p2 = -1
                                                 | otherwise = 0

---

minimax播放器（board:>boards）| maximum'[（isWinner player b（minimax'player））|（b:>bs）bs）我发现另一篇帖子讨论了我在这里遇到的同样问题：

答案如下：

minimax player (board :> []) = (0 :> [])

minimax :: Player -> Rose Board -> Rose Int
minimax p (r :> [])   | hasWinner r == Just P1 = 1    :> []
                      | hasWinner r == Just P2 = (-1) :> []
                      | otherwise              = 0    :> []
minimax P1 (r :> rs) = maximum (map root xs) :> xs
    where xs = map (minimax (nextPlayer P1)) rs

minimax P2 (r :> rs) = minimum (map root xs) :> xs
    where xs = map (minimax (nextPlayer P2)) rs

我希望这至少能在将来帮助别人。
本回答中使用的功能包括：

root :: Rose a -> a
root (a :> bs) = a 

nextPlayer :: Player -> Player
nextPlayer P1 = P2
nextPlayer P2 = P1

hasWinner :: Board -> Maybe Player

minimum :: Ord a => [a] -> a
maximum :: Ord a => [a] -> a

干杯