https://leetcode-cn.com/problems/longest-substring-without-repeating-characters/submissions/

class Solution:
    def lengthOfLongestSubstring(self, s: str) -> int:
        maxLengh = 0
        nowStr = ''
        index = 0
        indexFlag = 0
        while index < len(s):
            if nowStr == '':
                nowStr = s[index]
                indexFlag = index
            else:
                if s[index] in nowStr:
                    nowStr = ''
                    #从上次开始计算的下一个继续开始判断
                    index = indexFlag
                else:
                    nowStr += s[index]
            if len(nowStr) > maxLengh:
                maxLengh = len(nowStr)
            index += 1
            
        return maxLengh