// 1456. Maximum Number of Vowels in a Substring of Given Length #include "leetcode.h" /* * given a string 's' and an integer 'k', return the maximum * number of vowel letters in any substring of 's' with length * 'k'. vowel letters in english are 'a e i o u' */ class Solution { public: int maxVowels(string s, int k) { int count = 0, counting = 0; unordered_set bag = {'a', 'e', 'i', 'o', 'u'}; for (int i = 0, local = 0; i < s.size(); i++) { local += bag.count(s[i]); if (i - k >= 0) local -= bag.count(s[i - k]); count = max(count, local); } return count; } }; int main() { Solution obj; cout << obj.maxVowels("abciiidef", 3); // expect: 3 cout << obj.maxVowels("aeiou", 2); // expect: 2 cout << obj.maxVowels("leetcode", 3); // expect: 2 }