LeetCode 3541: Find Most Frequent Vowel and Consonant

Meta Data

#

Difficulty: easy First Attempt: 2025-05-10

• Submissions: Accepted (first try)

Approach

#

Count characters with Counter, then take the maximum within vowels and within consonants (String Template 4). A class with no characters counts as 0, via max(..., default=0).

My Solution

#

I originally sorted the Counter by count before scanning it; the sort is unnecessary, just take the maximums:

class Solution:
    def maxFreqSum(self, s: str) -> int:
        vowels = set("aeiou")
        cnt = Counter(s)
        best_v = max((v for c, v in cnt.items() if c in vowels), default=0)
        best_c = max((v for c, v in cnt.items() if c not in vowels), default=0)
        return best_v + best_c

Complexity

#

Time O(n), space O(1) (at most 26 characters).

Mistakes to Avoid

#

• With no characters in a class, max on an empty sequence raises; pass default=0.

Interview Explanation

#

I count each character, take the maximum among vowels and among consonants, and return their sum, using 0 for a missing class. Time O(n).