Given an array of integers arr, write a function that returns true if and only if the number of occurrences of each value in the array is unique. using hashmap
import java.util.*; class Solution { public boolean uniqueOccurrences(int[] arr) { HashMap<Integer,Integer> hash = new HashMap<>(); for(int i = 0;i<arr.length;i++){ if(hash.containsKey(arr[i])){ hash.put(arr[i],hash.get(arr[i])+1); }else{ hash.put(arr[i],1); } } for(int i = 0;i<arr.length;i++){ for(int j = i+1;j<arr.length-1;j++){ if(arr[i]!=arr[j] && hash.get(arr[i])==hash.get(arr[j])){ return false; } } } return true; } }