public class Solution
extends Object
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 <= 105
* `s` consists of lowercase English letters.
* `1 <= k <= s.length`