Find most frequent vowel and consonant

Hash Table String Counting

89.3% acceptance

Feb 25, 2026

423

You are given a string s consisting of lowercase English letters. Find the vowel ('a','e','i','o','u') with maximum frequency and the consonant with maximum frequency. Return the sum of the two frequencies. If no vowels or no consonants, frequency is 0.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn max_freq_sum(s: String) -> i32 {
    let vowels = b"aeiou";
    let mut freq = [0i32; 26];
    for b in s.bytes() {
      freq[(b - b'a') as usize] += 1;
    }
    let max_vowel = (0..26u8)
      .filter(|&i| vowels.contains(&(b'a' + i)))
      .map(|i| freq[i as usize])
      .max()
      .unwrap_or(0);
    let max_consonant = (0..26u8)
      .filter(|&i| !vowels.contains(&(b'a' + i)))
      .map(|i| freq[i as usize])
      .max()
      .unwrap_or(0);
    max_vowel + max_consonant
  }
}