Given an array of integers arr, return true if the number of occurrences of each value in the array is unique or false otherwise.
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.
Input: arr = [1,2] Output: false
Input: arr = [-3,0,1,-3,1,1,1,-3,10,0] Output: true
1 <= arr.length <= 1000 -1000 <= arr[i] <= 1000