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;
}
}