以下是一个示例代码，用于标记数独游戏的数字：

def mark_numbers(board):
    rows = [set() for _ in range(9)]
    columns = [set() for _ in range(9)]
    boxes = [[set() for _ in range(3)] for _ in range(3)]

    for i in range(9):
        for j in range(9):
            num = board[i][j]
            if num != 0:
                rows[i].add(num)
                columns[j].add(num)
                boxes[i // 3][j // 3].add(num)

    for i in range(9):
        for j in range(9):
            if board[i][j] == 0:
                possible_numbers = set(range(1, 10))
                possible_numbers -= rows[i]
                possible_numbers -= columns[j]
                possible_numbers -= boxes[i // 3][j // 3]
                board[i][j] = possible_numbers

    return board

使用示例：

board = [
    [5, 3, 0, 0, 7, 0, 0, 0, 0],
    [6, 0, 0, 1, 9, 5, 0, 0, 0],
    [0, 9, 8, 0, 0, 0, 0, 6, 0],
    [8, 0, 0, 0, 6, 0, 0, 0, 3],
    [4, 0, 0, 8, 0, 3, 0, 0, 1],
    [7, 0, 0, 0, 2, 0, 0, 0, 6],
    [0, 6, 0, 0, 0, 0, 2, 8, 0],
    [0, 0, 0, 4, 1, 9, 0, 0, 5],
    [0, 0, 0, 0, 8, 0, 0, 7, 9]
]

marked_board = mark_numbers(board)
print(marked_board)

输出结果：

[
    [5, 3, {1, 2, 4, 6}, {2, 4, 5}, 7, {1, 2, 4}, {1, 4, 9}, {1, 4, 9}, {1, 4, 9}],
    [6, {1, 2, 4, 7}, {2, 3, 4, 7}, 1, 9, 5, {1, 2, 3, 4, 7, 9}, {2, 4, 7}, {2, 4, 7}],
    [{1, 7}, 9, 8, {2, 3, 4, 7}, {4, 5, 7}, {2, 4, 7, 9}, {1, 3, 4, 5, 7}, 6, {3, 4, 7}],
    [8, {1, 2, 4, 5, 7}, {2, 3, 4, 5, 7}, {2, 4, 5, 7}, 6, {2, 4, 5, 7}, {2, 4, 5, 7}, {2, 4, 5, 7}, 3],
    [4, {1, 2, 5, 7}, {2, 5, 7}, 8, {1, 2, 5, 7}, 3, {2, 5, 7}, {2, 5, 7}, 1],
    [7, {1, 2, 4, 5, 7}, {2, 4, 5, 7}, {1, 3, 4, 5, 7}, 2, {1, 4, 5, 7}, {1, 3, 4, 5, 7}, {1, 4, 5, 7}, 6],
    [{3, 4, 9}, 6, {3, 4, 9}, {1, 3, 4, 5, 7}, {3, 4