@[FanYongchen](/user/263374) 建议这样
$$\small{f[i][j][k][l]=\max(\max(f[i-1][j][k][l],f[i][j-1][k][l])+a[i][j],\max(f[i][j][k-1][l],f[i][j][k][l-1])+a[k][l])}$$
by fjy666 @ 2021-09-02 09:59:58
@[fjy666](/user/366338) thx，但能不能证明一下上面那个是错的呢
by FanYongchen @ 2021-09-02 21:19:04
@[FanYongchen](/user/263374) 我觉得您 $\LaTeX$ 炸了
by xinglian @ 2021-09-03 19:06:59