vector<int> nextGreaterElement(vector<int>& nums1, vector<int>& nums2) {
        stack<int> s;
        const int N =1e5;
        vector<int> ans;
        vector<int> v(N);
        int n=nums2.size();
        s.push(nums2[n-1]);
        v[nums2[n-1]]=-1;
        
        for(int i=nums2.size()-2;i>=0;--i)
        {
             if(nums2[i]<(s.top()))
            {
                
                v[nums2[i]]=s.top();
                s.push(nums2[i]);
            }
            else
            {
                while(!s.empty() && s.top()<nums2[i]  )//order matters in &&
                s.pop();
                if(s.empty())
                v[nums2[i]]=-1;
                else
                v[nums2[i]]=s.top();
                s.push(nums2[i]);
            }
        }
        for(int j=0;j<nums1.size();++j)
        {
            ans.push_back(v[nums1[j]]);
        }


        return ans;
    }