> For the complete documentation index, see [llms.txt](https://hao-fu-1.gitbook.io/oj/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hao-fu-1.gitbook.io/oj/multiple-pointers/sliding-window/static-size/1456.-maximum-number-of-vowels-in-a-substring-of-given-length.md).

# 1456. Maximum Number of Vowels in a Substring of Given Length

https\://leetcode.com/problems/maximum-number-of-vowels-in-a-substring-of-given-length/

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).

**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.
```

**Example 4:**

```
Input: s = "rhythms", k = 4
Output: 0
Explanation: We can see that s doesn't have any vowel letters.
```

**Example 5:**

```
Input: s = "tryhard", k = 4
Output: 1
```

**Constraints:**

* `1 <= s.length <= 10^5`
* `s` consists of lowercase English letters.
* `1 <= k <= s.length`

返回长度为k的且元音字符最多的子数组含的元音字符数。固定长度子数组 => static window。

```python
class Solution:
    def maxVowels(self, s: str, k: int) -> int:
        l = r = res = w = 0
        for r in range(k):
            if s[r] in 'aeiou':
                w += 1
                res = w
        for r in range(k, len(s)):
            if s[r] in 'aeiou':
                w += 1
            if s[l] in 'aeiou':
                w -= 1
            l += 1
            res = max(w, res)
        return res
            
```