枫林无线

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

最长子窜

class Solution:
    def lengthOfLongestSubstring(self, s: str) -> int:
        st = {}
        i=0
        max1 = 0
        for j in range(len(s)):
            if s[j] in st:
                i = max(st[s[j]], i)#起始位置换到原始重复位置的后一位，如ab遇到a就变成ba去继续遇下一位
            max1 = max(max1, j - i + 1)
            st[s[j]] = j+1
        return max1