LeetCode题解(1100)：长度为K的无重复字符子串(Python)

题目：​​原题链接​​（中等）

标签：滑动窗口、哈希表、字符串

解法一：

class Solution:
    def numKLenSubstrNoRepeats(self, s: str, k: int) -> int:
        count = [0] * 26

        if len(s) < k:
            return 0

        for i in range(k):
            a = ord(s[i]) - 97
            count[a] += 1

        ans = 1 if max(count) <= 1 else 0

        for i in range(k, len(s)):
            a1 = ord(s[i]) - 97
            count[a1] += 1
            a2 = ord(s[i - k]) - 97
            count[a2] -= 1
            if max(count) <= 1:
                ans += 1

        return