洛谷P1063_区间dp

#include <cstdio>
#include <algorithm>

using namespace std;

const int maxn = 222;

int a[maxn];
int dp[maxn][maxn];
int n;

int main()
{
    int i, k, len, l, r;
    scanf("%d", &n);
    for(i = 1; i <= n; ++i)
        scanf("%d", &a[i]), a[n+i]=a[i];//环转环链技巧
    int ans = 0;
    for(len = 2; len <= n; ++len)//枚举区间长度
        for(l = 1; l+len-1 < 2*n; ++l)//枚举区间左端点
        {
            r = l + len - 1;//区间右端点
            for(k = l; k < r; ++k)//枚举断点
                dp[l][r] = max(dp[l][r], dp[l][k]+dp[k+1][r]+a[l]*a[k+1]*a[r+1]);
            ans = max(ans, dp[l][r]);
        }
    printf("%d\n", ans);
    return 0;
}