Given an array of integers arr , return true if the number of occurrences of each value in the array is unique or false otherwise . Example 1: Input: arr = [1,2,2,1,1,3] Output: true Explanation: The value 1 has 3 occurrences, 2 has 2 and 3 has 1. No two values have the same number of occurrences. Example 2: Input: arr = [1,2] Output: false Example 3: Input: arr = [-3,0,1,-3,1,1,1,-3,10,0] Output: true Constraints: 1 <= arr.length <= 1000 -1000 <= arr[i] <= 1000 Solution: class Solution { public boolean uniqueOccurrences ( int [] arr ) { Map < Integer , Integer > mp = new HashMap <>(); Arrays . stream (arr). forEach ( a -> mp . put (a, mp . getOrDefault (a, 0 )+ 1 ) ); long distinctCount = mp . values (). stream (). distinct (). count (); return distinctCount == mp . values (). size (); } }