python实现leetcode之3. 无重复字符的最长子串

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

解题思路

一遍扫描，碰到出现过的字符时:
1.更新更新当前不重复字符串的开始下标
2.如果不包括当前字符的不重复字符串到目前为止最长，更新rtv

代码

class Solution(object):
    def lengthOfLongestSubstring(self, s):
        """
        :type s: str
        :rtype: int
        """
        rtv = 0
        seen = {}
        start_idx = 0  # 当前无重复字符串的开始位置
        for idx, c in enumerate(s):
            if seen.get(c, -1) >= start_idx:
                # 更新当前不重复字符串的开始下标
                rtv = max(rtv, idx-start_idx)
                start_idx = seen[c] + 1
            seen[c] = idx
        return max(rtv, len(s)-start_idx)

执行效果图