1207.独一无二的出现次数

class Solution{
    public boolean uniqueOccurrences(int[] arr){
        Map<Integer,Integer>occur=new HashMap<Integer,Integer>();
        for(int x:arr){
            occur.put(x,occur.getOrDrfault(x,0)+1);        
        }    
        Set<Integer>times=new HashSet<Integer>();
        for(Map.Entry<Integer,Integer>x:occur.entrySet()){
            times.add(x.getValue());        
        }
        return times.size()==occur.size();
    }
}