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。

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