可以多加一圈0，使n * n的矩阵变为（n + 2）* (n + 2 )的矩阵，亲测可行 [加之前](https://www.luogu.com.cn/record/157047595) [加之后](https://www.luogu.com.cn/record/157050503) by XiongYingHao @ 2024-04-25 22:28:05