最长不含重复字符的子字符串

请从字符串中找出一个最长的不包含重复字符的子字符串，计算该最长子字符串的长度。
LeetCode链接：https://leetcode-cn.com/problems/zui-chang-bu-han-zhong-fu-zi-fu-de-zi-zi-fu-chuan-lcof/

class Solution:
    def lengthOfLongestSubstring(self, s: str) -> int:
        dic = {}
        res = tmp = 0
        for j in range(len(s)):
            i = dic.get(s[j], -1) # 获取索引 i
            dic[s[j]] = j # 更新哈希表
            tmp = tmp + 1 if tmp < j - i else j - i # dp[j - 1] -> dp[j]
            res = max(res, tmp) # max(dp[j - 1], dp[j])
        return res