class Solution {
    public List<String> subdomainVisits(String[] cpdomains) {
        //seperate string on space , take out value , then seperate on . and get 
        // all sub domains , make a HM and add (subdomains,value), keep updating the
        //value as you iterate the domains array
        
        HashMap<String,Integer> map = new HashMap<>();
        for(String domain : cpdomains){

            String[] arr = domain.split(" ");
            int visited = Integer.parseInt(arr[0]);

            //*** exception that split will not recogonize full stop for some reaso
            // so add comment lines, some how this works , just remember this ****
            String words[] = arr[1].split("\\.");
            
            //making sub domains and adding it to hashmap against their value
            StringBuilder word = new StringBuilder();

            //keep making domains in reverse and keep adding to map
            for(int i = words.length-1 ;i >= 0 ; i--){
                
                if(i == words.length - 1)
                word.append(words[i]);

                else{
                    word.insert(0,".");
                    word.insert(0,words[i]);
                }

                map.put(word.toString(),map.getOrDefault(word.toString(),0)+visited);
            }            
        }

        List<String> ans = new ArrayList<>();

        //iterate in hashmap and make answer
        for(String key : map.keySet()){
            StringBuilder sb = new StringBuilder();
            sb.append(map.get(key)+" " + key);
            
            ans.add(sb.toString());
        }
        return ans;
    }
}