1207. Unique Number of Occurrences

class Solution {
    public boolean uniqueOccurrences(int[] arr) {
        HashMap h = new HashMap();
        for(int i = 0; i < arr.length; i++) {
        	h.put(arr[i], h.getOrDefault(arr[i],0)+1);
        }
        if(h.size() == 0) return true;
        HashSet repeats = new HashSet();
       
        for (Integer a: h.keySet()) {
        	if(repeats.contains(h.get(a))) return false;
        	else repeats.add(h.get(a));
        }
        return true;
    }
}