pipioj 1019: 堆石子（区间dp）

http://www.pipioj.online/problem.php?id=1019

#define IO std::ios::sync_with_stdio(0);
#define bug(x)  cout<<#x<<" is "<<x<<endl
#include <bits/stdc++.h>
#define iter ::iterator
using namespace  std;
typedef long long ll;
typedef pair<int,int>P;
#define pb push_back
#define mk make_pair
#define se second
#define fi first
#define rs o*2+1
#define ls o*2
const ll mod=1e9+7;
const int N=1e3+5,M=3e6;


int d[N][N],a[N];

int n;
int main(){

    while(~scanf("%d",&n)){
        for(int i=1;i<=2*n-1;i++){
            for(int j=i+1;j<=2*n;j++)d[i][j]=1e9;
        }
        for(int i=1;i<=n;i++){
            scanf("%d",&a[i]);
            a[i+n]=a[i];
        }
        for(int i=1;i<=2*n;i++){
            a[i]+=a[i-1];
        }
        for(int l=n;l>=1;l--){
            for(int r=l+1;r<=n;r++){
                for(int k=l;k<r;k++){
                    d[l][r]=min(d[l][r],d[l][k]+d[k+1][r]+a[r]-a[l-1]);
                }
            }
        }
        int ans=d[1][n];
        printf("%d
",ans);
    }
    
}