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

longest-substring-without-repeating-characters.py

class Solution(object):
    def lengthOfLongestSubstring(self, s):
        """
        :type s: str
        :rtype: int
        """
        max_length = 0
        seen_dict = {}
        sub_start = 0
        for i, c in enumerate(s):
            if c in seen_dict:
                for j in range(sub_start, seen_dict[c]):
                    del seen_dict[s[j]]
                sub_start = seen_dict[c]+1
            seen_dict[c] = i
            if len(seen_dict) > max_length:
                max_length = len(seen_dict)
        return max_length