版权声明：欢迎大佬指正！ https://blog.csdn.net/sinat_36215255/article/details/82285342
之前写完了被吞了。。。
懒的再写一遍
#include <iostream>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <string>
#include <vector>
#include <map>
#include <queue>
#include <cmath>
#define ll long long
using namespace std;
const int maxn = 2e4+5;
const int mod = 233;
ll dp[2][maxn][210];
ll V[maxn];
ll sum[maxn];
int main()
{
int T;
scanf("%d",&T);
while(T--)
{
memset(dp,0,sizeof(dp));
int n;
scanf("%d",&n);
for(int i=1; i<=n; i++)
scanf("%lld",&V[i]);
sum[0] = 0;
for(int i=1; i<=n; i++)
sum[i] = sum[i-1]+V[i];
for(int i=n; i>=1; i--)
{
int mxj1 = n-i+1;
int mxj2 = sqrt(2.0*i) + 1;
for(int j=1; j<=min(mxj1,mxj2); j++)
{
if(i+j==n+1)
{
dp[0][i][j] = sum[n]-sum[i-1];
dp[1][i][j] = (-sum[n]+sum[i-1]);
continue;
}
if(i+j+j<=n+1)
{
dp[0][i][j] =dp[1][(i+j)][j];
dp[1][i][j] =dp[0][(i+j)][j];
}
if(i+j+j+1<=n+1)
{
dp[0][i][j] =min(dp[0][i][j],dp[1][(i+j)][j+1] );
dp[1][i][j] =max(dp[1][i][j],dp[0][(i+j)][j+1]);
}
dp[0][i][j] += (sum[i+j-1] - sum[i-1]);
dp[1][i][j] += (-sum[i+j-1] + sum[i-1]);
}
}
ll ans;
ans = dp[0][1][1];
if(n>=2)
ans = max(ans,dp[0][1][2]);
printf("%lld\n",ans);
}
return 0;
}