3591. Check if Any Element Has Prime Frequency

Problem Link

Description

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You are given an integer array nums.

Return true if the frequency of any element of the array is prime, otherwise, return false.

The frequency of an element x is the number of times it occurs in the array.

A prime number is a natural number greater than 1 with only two factors, 1 and itself.

 

Example 1:

Input: nums = [1,2,3,4,5,4]

Output: true

Explanation:

4 has a frequency of two, which is a prime number.

Example 2:

Input: nums = [1,2,3,4,5]

Output: false

Explanation:

All elements have a frequency of one.

Example 3:

Input: nums = [2,2,2,4,4]

Output: true

Explanation:

Both 2 and 4 have a prime frequency.

 

Constraints:

• 1 <= nums.length <= 100
• 0 <= nums[i] <= 100

Solution

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Python3

def generate_primes(n):
    isPrime = [True] * (n + 1)
    isPrime[0] = isPrime[1] = False
 
    for i in range(2, n + 1):
        if isPrime[i]:
            for j in range(i * i, n + 1, i):
                isPrime[j] = False
 
    return isPrime
 
isPrime = generate_primes(101)
 
class Solution:
    def checkPrimeFrequency(self, nums: List[int]) -> bool:
        N = len(nums)
        counter = Counter(nums)
 
        for v in counter.values():
            if isPrime[v]:
                return True
 
        return False