LeetCode daily problem P3541: Find the most frequent vowel and consonant

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Timeline

Timeline

2025-09-13

init

Counting sort

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Problem:

P3541Find the most frequent vowel and consonant

https://leetcode.cn/problems/find-most-frequent-vowel-and-consonant/description/?envType=daily-question&envId=2025-09-13

Use counting sort idea, trade space for time, complexity O(n)

ASCIIcode table

https://www.runoob.com/w3cnote/ascii.html

Counting sort

https://www.runoob.com/w3cnote/counting-sort.html

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

bool isVowel(char c)
{
        if (c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u' || c == 'A' || c == 'E' ||
            c == 'I' || c == 'O' || c == 'U') {
                return true;
        }
        return false;
}

int maxFreqSum(char *s)
{
        int len;
        int arr[58];
        len = strlen(s);

        memset(arr, 0, 58 * sizeof(int));

        for (int i = 0; i < len; i++) {
                arr[s[i] - 'A']++;
        }
        int vowel_max = 0;
        int consonant_max = 0;
        for (int i = 0; i < 58; i++) {
                if (isVowel('A' + i) && arr[i] > vowel_max) {
                        vowel_max = arr[i];
                }

                if (!isVowel('A' + i) && arr[i] > consonant_max) {
                        consonant_max = arr[i];
                }
        }
        return vowel_max + consonant_max;
}
int main()
{
        int n;
        n = maxFreqSum("successes");
        printf("%d", n);
}