GFG PTOD | 23 Feb | Next Greater Element | Medium level | STACK

vector<int> nextLargerElement(vector<int>& arr) {
        // code here
        int n = arr.size();
        vector<int> ans(n, -1);
        stack<int> st;
        for(int i=n-1; i>=0; i--) {
            while(!st.empty() && arr[i] >= st.top()) st.pop();
            if(!st.empty()) ans[i] = st.top();
            st.push(arr[i]);
        }
        return ans;
     }