Solution.cpp

class Solution {
public:
    int maxSumMinProduct(vector<int>& nums) {
        int n = nums.size();
        vector<int> left(n, -1);
        vector<int> right(n, n);
        stack<int> stk;
        for (int i = 0; i < n; ++i) {
            while (!stk.empty() && nums[stk.top()] >= nums[i]) {
                stk.pop();
            }
            if (!stk.empty()) {
                left[i] = stk.top();
            }
            stk.push(i);
        }
        stk = stack<int>();
        for (int i = n - 1; ~i; --i) {
            while (!stk.empty() && nums[stk.top()] > nums[i]) {
                stk.pop();
            }
            if (!stk.empty()) {
                right[i] = stk.top();
            }
            stk.push(i);
        }
        long long s[n + 1];
        s[0] = 0;
        for (int i = 0; i < n; ++i) {
            s[i + 1] = s[i] + nums[i];
        }
        long long ans = 0;
        for (int i = 0; i < n; ++i) {
            ans = max(ans, nums[i] * (s[right[i]] - s[left[i] + 1]));
        }
        const int mod = 1e9 + 7;
        return ans % mod;
    }
};