Minimax tic tac toe 并没有选择实际的最佳移动

Question

我为 Minimax AI 井字游戏编写了 python 代码。 然而，Minimax 实际并没有选择最佳着法。 第一步似乎总是选择右上角，而所有其他动作几乎都是随机的。 它很容易被击败，这似乎是我代码中某处的错误。 感谢您的任何帮助。

界面代码：

from tkinter import *
import customtkinter
import minimax

customtkinter.set_appearance_mode("Dark")
#creating CTk window for app
root = customtkinter.CTk()

#setting window width and height
root.geometry('500x300')


#Creating label
label = customtkinter.CTkLabel(master=root,
                               text="Tic Tac Toe",
                               width=120,
                               height=50,
                               font=("normal", 20),
                               corner_radius=8)
label.place(relx=0.25, rely=0.8, anchor=CENTER)

#Handling clicks
depth=9
def clickbutton(r, c):
    buttons[r][c]["text"]="X"
    board[r][c]="X"
    buttons[r][c]['state']=DISABLED

    label = customtkinter.CTkLabel(master=root,
                               text=checkwin(board),
                               width=120,
                               height=25,
                               corner_radius=8)
    label.place(relx=0.25, rely=0.9, anchor=CENTER)

    global depth
    depth-=1
    computerplay()
    depth-=1
    
    

#Button matrix
buttons = [
     [0,0,0],
     [0,0,0],
     [0,0,0]]
 
#Matrix identifying whether buttons are active or inactive
board=[[0,0,0],[0,0,0],[0,0,0]]
 
for i in range(3):
    for j in range(3):                                 
        buttons[i][j] = Button(height = 3, width = 6, font = ("Normal", 20),
                        command = lambda r = i, c = j : clickbutton(r,c))
        buttons[i][j].grid(row = i, column = j)



def computerplay():
    global depth
    bestmove=minimax.minimax(board, depth, 1)
    buttons[bestmove[0]][bestmove[1]]['text']="O"
    buttons[bestmove[0]][bestmove[1]]['state']=DISABLED
    board[bestmove[0]][bestmove[1]]="O"

def checkwin(b):
    score=minimax.evaluate(b)
    if score==10:
        return 'Computer won!'
    elif score==-10:
        return 'You won!'
    else:
        return 'Player vs. Computer'
    

root.mainloop() 

极小极大代码：

def change_board(board):
    return [
        [(cell == "O") - (cell == "X") for cell in row]
        for row in board
    ]

def empty_cells(board):
    return [(i, j) for i in range(3) for j in range(3) if board[i][j] == 0]

def game_over(board):
    return (evaluate(board) == 10 or evaluate(board) ==-10 or not empty_cells(board))
    
lines = (
    (0, 0, 1, 1, 2, 2),
    (0, 2, 1, 1, 2, 0),
    (0, 0, 0, 1, 0, 2),
    (1, 0, 1, 1, 1, 2),
    (2, 0, 2, 1, 2, 2),
    (0, 0, 1, 0, 2, 0),
    (0, 1, 1, 1, 2, 1),
    (0, 2, 1, 2, 2, 2)
)

def evaluate(board):
    def iswin(line):
        arow, acol, brow, bcol, crow, ccol = line
        if board[arow][acol] == board[brow][bcol] == board[crow][ccol]:
            return board[arow][acol]*10

    return next((win for win in map(iswin, lines) if win), 0)
    

def minimax(board, depth, player):
    best = (-1, -1, -11*player)

    if depth <= 0 or game_over(board):
        return (-1, -1, evaluate(board))  # must return same structure

    for x, y in empty_cells(board):
        board[x][y] = player
        score = minimax(board, depth - 1, -player)[2]  # only get the score
        board[x][y] = 0
        if (player == 1) == (score > best[2]):
            best = (x, y, score)  # only inject x, y when move is best

    return best

Answer 1

您的代码混淆了它存储在board中的值。 一方面有 minimax 模块，它在board中存储和期望值 -1、0 和 1（因为player是 1 或 -1），但另一方面，您在 GUI 端有存储"O"的代码或板数据结构中的"X" 。 这种混淆破坏了evaluate function 中使用的逻辑。

在您之前关于该主题的问题中，您有一个 function change_board ，它执行了从"X"和"O"值到 -1 和 1 的转换。但在这个问题中没有执行此转换。

因此，要解决此问题，请更改 GUI 管理代码中的这些行：

board[r][c]="X"
...
board[bestmove[0]][bestmove[1]]="O"

...到：

board[r][c]=-1
...
board[bestmove[0]][bestmove[1]]=1