H - 大水题

https://vjudge.net/contest/280305#problem/H

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
using namespace std;
int i,n,a[400],kk,k,len,ans,sum[400],dp[400][400];
int main(){
  while (~scanf("%d",&n)){
    for (i=1;i<=n;i++){
        scanf("%d",&a[i]);
        sum[i]=sum[i-1]+a[i];
    }
    for (i=n+1;i<=n+n;i++){
        a[i]=a[i-n];
        sum[i]=sum[i-1]+a[i];
    }
    memset(dp,0x3f3f3f,sizeof(dp));
    for (i=1;i<=n*2;i++)
        dp[i][i]=0;
    for (len=2;len<=n;len++)
    for (i=1;i<=n+n;i++){
        kk=i+len-1;
        if (kk>n*2) break;
        for (k=i;k<kk;k++)
            dp[i][kk]=min(dp[i][kk],dp[i][k]+dp[k+1][kk]+sum[kk]-sum[i-1]);
    }
    ans=1000000000;
    for (i=1;i<=n;i++)
        ans=min(ans,dp[i][i+n-1]);
    printf("%d ",ans);
    memset(dp,0,sizeof(dp));
    for (len=2;len<=n;len++)
    for (i=1;i<=n+n;i++){
        kk=i+len-1;
        if (kk>n*2) break;
        for (k=i;k<kk;k++)
            dp[i][kk]=max(dp[i][kk],dp[i][k]+dp[k+1][kk]+sum[kk]-sum[i-1]);
    }
    ans=-1000000;
    for (i=1;i<=n;i++)
        ans=max(ans,dp[i][i+n-1]);
    printf("%d\n",ans);
  }
}