next greater element i

//it is of the order of m*n........

class Solution {
public:
    vector<int> nextGreaterElement(vector<int>& nums1, vector<int>& nums2) {
        int n = nums2.size();
        stack<int> nextG;
        stack<int> temp;
        for(int i=n-1; i>=0; i--){
            if(temp.empty()){
                nextG.push(-1);
                temp.push(nums2[i]);
            }
            else if(temp.top()>nums2[i]){
                nextG.push(temp.top());
                temp.push(nums2[i]);
            }
            else{
                
                while(!temp.empty() && temp.top()<nums2[i]){
                    temp.pop();
                }
                if(!temp.empty()){
                    nextG.push(temp.top());
                }
                else{
                    nextG.push(-1);
                }
                temp.push(nums2[i]);
            }
        }
        vector<int> ans;
        while(!nextG.empty()){
            // cout<<nextG.top()<<" ";
            ans.push_back(nextG.top());
            nextG.pop();
        }
        
        vector<int> finalAns;
        for(int i=0; i<(int)nums1.size(); i++){
            for(int j=0; j<n; j++){
                if(nums1[i]==nums2[j]){
                    finalAns.push_back(ans[j]);
                    break;
                }
            }
        }
        return finalAns;
    }
};