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

Problem Link

Description

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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

Solution

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Python3

class Solution:
    def maxVowels(self, s: str, k: int) -> int:
        N = len(s)
        res = count = 0
        vowel = 'aeiou'
 
        for i, x in enumerate(s):
            if i >= k:
                count -= s[i - k] in vowel
 
            count += x in vowel
            
            if count > res:
                res = count
        
        return res