LeetCode-in-Java
1456. Maximum Number of Vowels in a Substring of Given Length
Medium
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', and 'u'.
Example 1:
Input: s = “abciiidef”, k = 3
Output: 3
Explanation: The substring “iii” contains 3 vowel letters.
Example 2:
Input: s = “aeiou”, k = 2
Output: 2
Explanation: Any substring of length 2 contains 2 vowels.
Example 3:
Input: s = “leetcode”, k = 3
Output: 2
Explanation: “lee”, “eet” and “ode” contain 2 vowels.
Constraints:
1 <= s.length <= 105sconsists of lowercase English letters.1 <= k <= s.length
Solution
public class Solution {
private boolean isVowel(char c) {
return c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u';
}
public int maxVowels(String s, int k) {
int maxVowelCount = 0;
int vowelCount = 0;
int i = 0;
int j = 0;
while (j < s.length()) {
char c = s.charAt(j);
if (isVowel(c)) {
vowelCount++;
}
if ((j - i + 1) == k) {
maxVowelCount = Math.max(maxVowelCount, vowelCount);
if (isVowel(s.charAt(i))) {
vowelCount--;
}
i++;
}
j++;
}
return maxVowelCount;
}
}