Leetcode: Longest Substring Without Repeating Characters

Question

Given a string, find the length of the longest substring without repeating characters. For example, the longest substring without repeating letters for “abcabcbb” is “abc”, which the length is 3. For “bbbbb” the longest substring is “b”, with the length of 1.

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Hide Similar Problems (H) Longest Substring with At Most Two Distinct Characters

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My Solution

class Solution(object):    def lengthOfLongestSubstring(self, s):        """        :type s: str        :rtype: int        """        if s=='':            return 0         res, start = 0, 0        dictn = {}        for ind in range(len(s)):            if s[ind] not in dictn:                dictn[s[ind]] = 1                res = max(res, len(dictn))            else:                while s[start]!=s[ind]:                    del dictn[s[start]]                    start += 1                start += 1        return res