尝试用了一下RMQ来做， 小数据可以得到正确结果， 但是最后超时了， 具体原因我也不清楚嘿嘿

class Solution {
public:
    const static int N = 100010;
    int f[N][17];
    int len[N];

    void init(vector<int>& nums)
    {
        int n = nums.size();
        for (int j = 0; j < 17; j ++ )
            for (int i = 1; i + (1 << j) - 1 <= n; i ++ )
                if (!j) f[i][j] = nums[i - 1];
                else f[i][j] = min(f[i][j - 1], f[i + (1 << j - 1)][j - 1]);

        for(int i = 1, j = 1, t = 0; i < N; i ++)
        {
            while(j <= i) j *= 2, t ++;
            len[i] = t - 1;
        }
    }

    int query(int l, int r)
    {
        int k = len[r - l + 1];
        return min(f[l][k], f[r - (1 << k) + 1][k]);
    }

    int maximumScore(vector<int>& nums, int k) {
        init(nums);
        long long ans = 0;

        for(int j = k; j < nums.size(); j ++)
        {
            for(int i = 0; i <= k; i ++)
                ans = max(ans, (long long)query(i + 1, j + 1) * (j - i + 1));
        }

        return ans;
    }
};