leetcode-190周赛-1456-定长子串中元音的最大数目

 

 

 

 提交：

class Solution:
    def maxVowels(self, s: str, k: int) -> int:
        n = len(s)
        dp = [0] * (n + 1)
        for i in range(n):
            if s[i] in "aeiou":
                dp[i + 1] = dp[i] + 1
            else:
                dp[i + 1] = dp[i]
        if k >= n:
            return dp[-1]
        res = 0
        for i in range(k-1,n):
            res = max(res,dp[i+1] - dp[i-k+1])
        return res
                

优化：

class Solution:
    def maxVowels(self, s: str, k: int) -> int:
        r = h = 0
        vowel = set('aeiou')
        for i, c in enumerate(s):
            if c in vowel: h += 1
            if i >= k and s[i-k] in vowel: h -= 1
            r = max(r, h)
        return r