LeetCode每日一题——T3. 无重复字符的最长子串（中）：滑动窗口

采用了 滑动窗口 的思想：

class Solution:
    def lengthOfLongestSubstring(self, s: str) -> int:
        _dict = set()
        counter = 0
        start = 0
        counter = 0
        temp = 0
        for i in range(len(s)):
            temp += 1
            while s[i] in _dict:
                _dict.remove(s[start])
                start += 1
                temp -= 1
            if temp > counter:
                counter = temp
            _dict.add(s[i])
        return counter

思路来源：
https://leetcode-cn.com/problems/longest-substring-without-repeating-characters/solution/hua-dong-chuang-kou-by-powcai/