GFG PTOD | 24 Feb | Stock span problem | Medium level | STACK

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