class Solution {
public:
    vector<int> nextGreaterElement(vector<int>& nums1, vector<int>& nums2) {
        map<int,int> m;


        vector<int> v;

        for(int i=nums2.size()-1;i>=0;i--){

            cout<<v.size()<<' ';
            if(v.size()==0){
                m[nums2[i]]==-1;
                v.push_back(nums2[i]);
                continue;
            }else{

                if(v.back()<nums2[i]&&v.size()>0){
                    v.pop_back();
                }else{
                    m[nums2[i]]=v.back();v.push_back(nums2[i]);
                }

            }

        }
        cout<<endl;

        for(auto i:m){
            cout<<i.first<<':'<<i.second<<' ';
        }

        return {};
    }
};