next greater element linked list

//Input: [1,2,1]
//Output: [2,-1,2]
//Explanation: The first 1's next greater number is 2;
//The number 2 can't find next greater number;
//The second 1's next greater number needs to search circularly, which is also 2.

<---------for vector------------>
vector<int> nextGreaterElements(vector<int>& nums) {
        int n = nums.size();
        vector<int> next(n, -1);
        stack<int> s; // index stack
        for (int i = 0; i < n * 2; i++) {
            int num = nums[i % n];
            while (!s.empty() && nums[s.top()] < num) {
                next[s.top()] = num;
                s.pop();
            }
            if (i < n) s.push(i);
        }
        return next;
    }

<-----------linked list------->
vector<int> nextLargerNodes(ListNode* head) {
        vector<int> res, stack;
        for (ListNode* node = head; node; node = node->next) {
            while (stack.size() && res[stack.back()] < node->val) {
                res[stack.back()] = node->val;
                stack.pop_back();
            }
            stack.push_back(res.size());
            res.push_back(node->val);
        }
        for (int i: stack) res[i] = 0;
        return res;
    }