P1880 [NOI1995] 石子合并

[NOI1995] 石子合并 - 洛谷

/*
 * @Description: To iterate is human, to recurse divine.
 * @Autor: Recursion
 * @Date: 2022-04-02 23:00:48
 * @LastEditTime: 2022-04-05 10:38:03
 */
#include <bits/stdc++.h>
#define LL long long 
using namespace std;
const int maxn = 1e8 + 10;
const int mod = 1e9 + 7;
const int INF = 1e9 + 10;
const int N = 1e4;
int n;
int a[N],dp[N][N],dp2[N][N];
int sum[N];//前缀和
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin >> n;
    for(int i = 1;i <= n + n;i ++){
        cin >> a[i];
        a[n + i] = a[i];
    }
    for(int i = 1;i <= 2*n;i ++)
        sum[i] = sum[i - 1] + a[i];
    // for(int i = 1;i <= n;i ++)
    //     cout << sum[i] << endl;
    for(int len = 1; len < n;len ++)
        for(int i = 1; i + len  < 2*n;i ++){
            int j = i + len ;
            dp[i][j] = maxn;
            dp2[i][j] = 0;
            for(int k = i;k < j;k ++){
                dp[i][j] = min(dp[i][j],dp[i][k] + dp[k + 1][j] + sum[j] - sum[i -1]);
                dp2[i][j] = max(dp2[i][j],dp2[i][k] + dp2[k + 1][j] + sum[j] - sum[i - 1]);
            }
        }
    int ans1 = maxn;
    int ans2 = 0;
    for(int i = 1;i <= n;i ++){
        ans1 = min(dp[i][i + n - 1],ans1);
        ans2 = max(dp2[i][i + n - 1],ans2);
    }
    cout << ans1 << endl << ans2;
    // for(int i = 1; i<= n;i ++){
    //     for(int j = 1; j <= n;j ++)
    //         cout << dp[i][j] << " ";
    //     cout << endl;
    // }

    return 0;
}