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

Solution:

• similar to 643. Maximum Average Subarray I. almost the same. its a sliding window technique

class Solution:
    def maxVowels(self, s: str, k: int) -> int:

        def isVowel(c):
            if c in set('aeiou'):
                return True
            else:
                return False

        ret = l = 0
        for i in range(k):
            if isVowel(s[i]):
                l += 1
        ret = l
        for i in range(0, len(s) - k):
            if isVowel(s[i]):
                l -= 1
            if isVowel(s[i + k]):
                l += 1
            if l > ret:
                ret = l
        return ret