51Nod - 1021 石子归并（区间DP）

#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <cstdio>
#include <cstring>
using namespace std;
typedef long long LL;
const int maxn = 1000 + 100;
#define INF 0x3f3f3f3f

int main()
{
    int n;
    scanf("%d", &n);
    int sum[maxn];
    int f[maxn][maxn];
    memset(f, 0, sizeof(f));

    for (int i = 1; i <= n; i++)
    {
        int x;
        scanf("%d", &x);
        sum[i] = sum[i-1]+x;
    }

    for (int len = 2; len <= n; len++)
    {
        for (int i = 1; i <= n; i++)
        {
            int j = i+len-1;
            f[i][j] = INF;
            for (int k = i; k < j; k++)
                f[i][j] = min(f[i][j], f[i][k]+f[k+1][j] + sum[j] - sum[i-1]);
        }
    }

    printf("%d\n", f[1][n]);
}