Description
https://leetcode.com/problems/unique-number-of-occurrences/
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.
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
Explanation
Count occurences and check if numers of occurences having the same.
Python Solution
class Solution:
def uniqueOccurrences(self, arr: List[int]) -> bool:
visited = {}
for num in arr:
visited[num] = visited.get(num, 0) + 1
values = set()
for key, value in visited.items():
if value in values:
return False
values.add(value)
return True- Time Complexity: O(N)
- Space Complexity: O(N)