3. Longest Substring Without Repeating Characters

题目来源：https://leetcode.com/problems/longest-substring-without-repeating-characters/

 自我感觉难度/真实难度：             写题时间时长：

 题意：

 分析：

 自己的代码：

class Solution(object):
    def lengthOfLongestSubstring(self, s):
        """
        :type s: str
        :rtype: int
        """
        start=maxlen=0
        sueedChar={}
        for i in range(len(s)):
            if s[i] in sueedChar and start<=sueedChar[s[i]]:
                start=sueedChar[s[i]]+1
            else:
                maxlen=max(maxlen,i-start+1)
            sueedChar[s[i]]=i
        return maxlen

start<=sueedChar[s[i]]，主要是针对出现两个字母重复但是临近的时候。

代码效率/结果：

Runtime: 48 ms, faster than 89.58% of Python online submissions forLongest Substring Without Repeating Characters.

Memory Usage: 12.7 MB, less than 6.10% of Python online submissions forLongest Substring Without Repeating Characters.

 优秀代码：

代码效率/结果：

 自己优化后的代码：

 反思改进策略：