21. 1207. Unique Number of Occurrences

class Solution {
    public boolean uniqueOccurrences(int[] arr) {
         HashMap<Integer,Integer> hm = new HashMap<>();
        HashSet<Integer>hs = new HashSet<>();

        for(int i:arr){
            hm.put(i,hm.getOrDefault(i, 0)+1);
        }
        for(HashMap.Entry<Integer,Integer> e: hm.entrySet()){
            if(hs.contains(e.getValue())){
                return false;
            }
            hs.add(e.getValue());
        }
      return true;
    }
}