1207. Unique Number of Occurrences
Easy
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
class Solution:
def uniqueOccurrences(self, arr: List[int]) -> bool:
hash_set = {}
for num in arr:
if num in hash_set:
hash_set[num] = hash_set[num]+1
else:
hash_set[num] = 1
return len(hash_set.values())== len(set(hash_set.values()))