Find Most Frequent Vowel and Consonant - Practice Coding Problems

Find Most Frequent Vowel and Consonant - Problem

You are given a string s consisting of lowercase English letters ('a' to 'z'). Your task is to:

Find the vowel (one of 'a', 'e', 'i', 'o', or 'u') with the maximum frequency.
Find the consonant (all other letters excluding vowels) with the maximum frequency.
Return the sum of the two frequencies.

Note: If multiple vowels or consonants have the same maximum frequency, you may choose any one of them. If there are no vowels or no consonants in the string, consider their frequency as 0.

The frequency of a letter x is the number of times it occurs in the string.

Input & Output

Example 1 — Mixed Vowels and Consonants

$ Input: s = "hello"

› Output: 3

💡 Note: Vowel frequencies: e=1, o=1. Consonant frequencies: h=1, l=2. Max vowel freq = 1, max consonant freq = 2. Result: 1 + 2 = 3

Example 2 — Repeated Vowel

$ Input: s = "aabbcc"

› Output: 4

💡 Note: Vowel frequencies: a=2. Consonant frequencies: b=2, c=2. Max vowel freq = 2, max consonant freq = 2. Result: 2 + 2 = 4

Example 3 — Only Vowels

$ Input: s = "aeiou"

› Output: 1

💡 Note: All characters are vowels with frequency 1 each. No consonants. Max vowel freq = 1, max consonant freq = 0. Result: 1 + 0 = 1

Constraints

1 ≤ s.length ≤ 1000
s consists only of lowercase English letters

Visualization

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Understanding the Visualization

Input String

Given string with lowercase letters to analyze

Count & Categorize

Count frequencies and separate vowels from consonants

Find Maximums

Get maximum frequency from each category and sum them

Key Takeaway

🎯 Key Insight: Categorize letters while counting to track separate maximums efficiently

Asked in

G Google 35 a Amazon 28 M Microsoft 22 f Facebook 18

The key insight is to separate vowels and consonants while counting frequencies. Track maximum frequencies for each category and return their sum. Best approach uses single pass frequency counting with simultaneous maximum tracking. Time: O(n), Space: O(1).

Common Approaches

Approach	Time	Space	Notes
✓ Brute Force - Count Each Letter	O(n²)	O(1)	Count frequency of each letter individually, then find max vowel and consonant
Single Pass Optimized	O(n)	O(1)	Track maximum frequencies while counting in a single pass
Frequency Count with Hash Map	O(n)	O(1)	Single pass to count all frequencies, then find maximum vowel and consonant

Brute Force - Count Each Letter — Algorithm Steps

Step 1: For each unique letter, count its frequency by scanning entire string
Step 2: Check if letter is vowel or consonant and update respective maximum
Step 3: Return sum of maximum vowel and consonant frequencies

Visualization

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Step-by-Step Walkthrough

Find Unique Letters

Identify all unique characters in the string

Count Each Letter

For each unique letter, scan entire string to count occurrences

Track Maximums

Keep track of maximum vowel and consonant frequencies

Code -

solution.c — C

#include <stdio.h>
#include <string.h>
#include <stdbool.h>

bool isVowel(char c) {
    return c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u';
}

int solution(char* s) {
    int len = strlen(s);
    int maxVowelFreq = 0;
    int maxConsonantFreq = 0;
    bool seen[26] = {false};
    
    // Process each unique character
    for (int i = 0; i < len; i++) {
        char ch = s[i];
        if (seen[ch - 'a']) continue;
        seen[ch - 'a'] = true;
        
        // Count frequency of this character
        int freq = 0;
        for (int j = 0; j < len; j++) {
            if (s[j] == ch) {
                freq++;
            }
        }
        
        if (isVowel(ch)) {
            if (freq > maxVowelFreq) {
                maxVowelFreq = freq;
            }
        } else {
            if (freq > maxConsonantFreq) {
                maxConsonantFreq = freq;
            }
        }
    }
    
    return maxVowelFreq + maxConsonantFreq;
}

int main() {
    char s[1001];
    fgets(s, sizeof(s), stdin);
    s[strcspn(s, "\n")] = 0;
    int result = solution(s);
    printf("%d\n", result);
    return 0;
}

Time & Space Complexity

Time Complexity

⏱️

O(n²)

For each of up to 26 unique letters, we scan the entire string of length n

⚠ Quadratic Growth

Space Complexity

O(1)

Only using variables to track counts and maximums

✓ Linear Space

23.4K Views

Medium Frequency

~15 min Avg. Time

856 Likes

Ln 1, Col 1

Smart Actions

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Input & Output

Constraints

Visualization

Related Problems

Common Approaches

Brute Force - Count Each Letter — Algorithm Steps

Visualization

Code -

Time & Space Complexity

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