刚刚抽到了70
[记录](https://www.luogu.com.cn/record/116356757)
by NumberTrart @ 2023-07-19 11:54:15
又抽到了80
[记录](https://www.luogu.com.cn/record/116410765)
by NumberTrart @ 2023-07-19 16:10:25
https://www.luogu.com.cn/record/116581483
by 13867196971a @ 2023-07-20 15:01:38
@[NumberTrart](/user/602932) 这代码很长而很不稳定，可以试试我这个，全AC
```
#include <bits/stdc++.h>
using namespace std;
const int maxn=2000;
inline void print(__int128 x)
{
if(x>9)print(x/10);
putchar(x%10+'0');
}
int n,m;
int a[maxn];
__int128 ans;
__int128 f[maxn][maxn];
int main()
{
ios::sync_with_stdio(false);
cin>>n>>m;
for(int i=1;i<=n;i++)
{
for(int j=1;j<=m;j++)
{
cin>>a[j];
}
memset(f,0,sizeof(f));
for(int len=0;len<=m;len++)
{
for(int l=1;l<=m-len;l++)
{
int r=l+len;
f[l][r]=2*max(f[l+1][r]+a[l],f[l][r-1]+a[r]);
}
}
ans+=f[1][m];
}
print(ans);
return 0;
}
```
by all___right @ 2023-07-22 16:31:48
@[yejingzhi](/user/1037639) 求此处l与r的含义（不太懂
by realheizi @ 2023-07-25 14:39:41
```
f[l][r]=2*max(f[l+1][r]+a[l],f[l][r-1]+a[r])
```
看这行代码，你会发现，都是用来统计的（doge）
by all___right @ 2023-07-25 16:26:36
@[xuzichen123](/user/780067)
你再看看，有老师的话问老师
by all___right @ 2023-07-25 16:27:39
本11岁野生蒟蒻表示没办法
by all___right @ 2023-07-25 16:28:10
@[yejingzhi](/user/1037639) 老师让我自己想（喜
by realheizi @ 2023-07-25 16:35:04
喜感，注：我的验证码HMMD
by all___right @ 2023-07-25 16:36:21