1207.unique-number-of-occurrences.py

from lc import *

# https://leetcode.com/problems/unique-number-of-occurrences/discuss/949934/python-3-one-line

class Solution:
    def uniqueOccurrences(self, arr: List[int]) -> bool:
        return len(Counter(arr))==len(set(Counter(arr).values()))

class Solution:
    def uniqueOccurrences(self, a: List[int]) -> bool:
        return eq(*map(len,map(set,(a,Counter(a).values()))))

class Solution:
    def uniqueOccurrences(self, arr: List[int]) -> bool:
        return len(set(arr))==len(set(Counter(arr).values()))

class Solution:
    def uniqueOccurrences(self, a: List[int]) -> bool:
        return len(c:=Counter(a))==len({*c.values()})

class Solution:
    def uniqueOccurrences(self, a: List[int]) -> bool:
        return len({*a})==len({*Counter(a).values()})

test('''

1207. Unique Number of Occurrences
Easy

2232

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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

Example 4:

Input: arr = [1, 2,2, 3,3,3, 4,4,4,4]
Output: true

Constraints:

1 <= arr.length <= 1000
-1000 <= arr[i] <= 1000

''')