Count of Substrings Containing Every Vowel and K Consonants I - Problem

#include <stdio.h>
#include <stdlib.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* word, int k) {
    int count = 0;
    int n = strlen(word);
    
    for (int i = 0; i < n; i++) {
        for (int j = i; j < n; j++) {
            bool vowelsSeen[5] = {false};
            int consonantCount = 0;
            
            for (int idx = i; idx <= j; idx++) {
                char c = word[idx];
                if (isVowel(c)) {
                    if (c == 'a') vowelsSeen[0] = true;
                    else if (c == 'e') vowelsSeen[1] = true;
                    else if (c == 'i') vowelsSeen[2] = true;
                    else if (c == 'o') vowelsSeen[3] = true;
                    else if (c == 'u') vowelsSeen[4] = true;
                } else {
                    consonantCount++;
                }
            }
            
            int vowelCount = 0;
            for (int v = 0; v < 5; v++) {
                if (vowelsSeen[v]) vowelCount++;
            }
            
            if (vowelCount == 5 && consonantCount == k) {
                count++;
            }
        }
    }
    
    return count;
}

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