3306. Count of Substrings Containing Every Vowel and K Consonants II

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

    long long atLeastK(string& word, int k) {
        int n = word.size();
        long long ans = 0;
        int consonants = 0;
        int left = 0;
        unordered_map<char, int> vowel_map;

        for (int right = 0; right < n; right++) {
            if (isVowel(word[right])) {
                vowel_map[word[right]]++;
            } else {
                consonants++;
            }

            while (vowel_map.size() == 5 && consonants >= k) {
                ans += n - right;
                if (isVowel(word[left])) {
                    vowel_map[word[left]]--;
                    if (vowel_map[word[left]] == 0) {
                        vowel_map.erase(word[left]);
                    }
                } else {
                    consonants--;
                }
                left++;
            }
        }
        return ans;
    }

    long long countOfSubstrings(string word, int k) {
        return atLeastK(word, k) - atLeastK(word, k + 1);
    }
};