Unique Number of Occurrences
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
trueThe value 1 has 3 occurrences, 2 has 2 occurrences, and 3 has 1 occurrence, so no two values have the same number of occurrences.
Example 2
Input
arr = [1,2]Output
falseThe values 1 and 2 each occur once, so the occurrence counts are not unique.
Constraints
- 1 <= arr.length <= 1000
- -1000 <= arr[i] <= 1000