Lintcode 384. Longest Substring Without Repeating Characters (Medium) (Python)，lintcoderepeating

Longest Substring Without Repeating Characters

Description:

Given a string, find the length of the longest substring without repeating characters.

Example
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.

Challenge
O(n) time

Code:

class Solution:
    """
    @param s: a string
    @return: an integer
    """
    def lengthOfLongestSubstring(self, s):
        # write your code here
        if len(s)<2:
            return len(s)

        dic = {}
        start = 0
        res = 0

        for i in range(len(s)):
            if s[i] in dic:
                res = max(res, len(dic))
                while s[i] in dic:
                    dic.pop(s[start])
                    start += 1

            dic[s[i]]=1

        res = max(res, len(dic))  
        return res