Problem

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:

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Input: s = "abciiidef", k = 3
Output: 3
Explanation: The substring "iii" contains 3 vowel letters.

Example 2:

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Input: s = "aeiou", k = 2
Output: 2
Explanation: Any substring of length 2 contains 2 vowels.

Example 3:

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Input: s = "leetcode", k = 3
Output: 2
Explanation: "lee", "eet" and "ode" contain 2 vowels.

Constraints:

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

Solve

醜醜

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class Solution:
    def maxVowels(self, s: str, k: int) -> int:
        l , r = 0 , 0
        vowel = "aeiou"
        
        res = 0
        
        for i in range(k):
            if s[i] in vowel:
                res +=1
        max_res=res

        for i in range( k, len(s) ):
            if s[i] in vowel:
                res +=1

            if s[ i-k ]  in vowel:
                res -= 1
            max_res = max(max_res,res)

        return max_res