class Solution {
    public String mostCommonWord(String paragraph, String[] banned) {
        paragraph = paragraph.toLowerCase();
        String[] ss = paragraph.split("[^\\w']+|' *");
        Map<String,Integer> map = new HashMap<>();
        for (int i=0;i<ss.length;i++){
            if (map.containsKey(ss[i])){
                int n = map.get(ss[i])+1;
                map.put(ss[i],n++);
            }
            else map.put(ss[i],0);
        }
        List<Map.Entry<String,Integer>> list = new ArrayList<>(map.entrySet());
        list.sort(Map.Entry.comparingByValue());
        int i = list.size()-1;
        while (i>=0){
            int j;
            for (j =0;j<banned.length;j++){
                if (banned[j].toLowerCase().equals(list.get(i).getKey())){
                    i--;
                    break;
                }
            }
            if (j != banned.length)
                continue;
            break;
        }
        return list.get(i).getKey();
    }
}