Leetcode May Daily Challenge 5.py

class Solution:
    def maxVowels(self, s: str, k: int) -> int:
        s_list = list(s)
        vowels = ['a', 'e', 'i', 'o', 'u']
        cnt = 0
        for i in range(k):
            if s_list[i] in vowels:
                cnt = cnt + 1
        max_num = cnt
        for end in range(k,len(s)):
            start = end - k + 1
            if s_list[start-1] in vowels:
                cnt = cnt - 1
            if s_list[end] in vowels:
                cnt = cnt + 1
            max_num = max(max_num, cnt)
        return max_num