學習筆記 | 無重複字符最長子串

01 無重複字符最長子串

• 快慢指針

class Solution(object):
    def lengthOfLongestSubstring(self, s):
        """
        :type s: str
        :rtype: int
        """
        ans = 0
        if not s:
            return ans
        
        i = 0
        j = 0
        dic = {}
        
        while j < len(s):
            if s[j] in dic:
                i = max(dic[s[j]]+1,i)
            
            dic[s[j]] = j
            ans = max(ans,j-i+1)
            
            j += 1
        return ans