【python-leetcode03-滑动窗口法】无重复字符的最大子串

class Solution:
    def lengthOfLongestSubstring(self, s: str) -> int:
        tmp = 0 #用于记录满足条件得最大值
        for i in range(1,len(s)+1):#步长从1到len(s)+1
            for j in range(len(s)-i+1):#窗口左端
                if len(set(s[j:j+i])) == len(s[j:j+i]):#如果取集合后的长度和原始窗口长度一样，说明这个窗口是不含重复字符的
                    tmp = max(tmp,i)#更新tmp的值
        return tmp #最后返回即可

class Solution:
    def lengthOfLongestSubstring(self, s: str) -> int:
        if len(s) == 0:
            return 0
        if len(s) == 1:
            return 1
        start = 0  # 滑动窗口左端
        max_num = 0  # 用于计算最大值
        from collections import defaultdict
        hash = defaultdict(int)  
        for i in range(len(s)):
            hash[s[i]]+=1
            while len(hash)<self.dictSum(hash):
                hash[s[start]] -= 1
                if hash[s[start]] == 0:
                    del hash[s[start]]
                start += 1
            max_num = max(max_num,i-start+1)
        return max_num
    def dictSum(self,dic):
        sum = 0
        for i in dic:
            sum += dic[i]
        return sum