本文共 1022 字，大约阅读时间需要 3 分钟。

class Solution:    def minWindow(self, s: str, t: str) -> str:        def dic_equal(dic1,dic2):            for key in dic1:                if dic2[key] < dic1[key]:                    return False            return True        t_dic = {   }        for t1 in t:            if t1 not in t_dic:                t_dic[t1] = 1            else:                t_dic[t1] = t_dic[t1] + 1                tmp_dic = {   }        for key in t_dic.keys():            tmp_dic[key] = 0        start = 0        res_start = -1        ans = len(s)        for i in range(len(s)):            if s[i] in t_dic:                tmp_dic[s[i]] = tmp_dic[s[i]] + 1            while dic_equal(t_dic, tmp_dic):                if i-start+1 <= ans:                    ans = i-start+1                    res_start = start                if s[start] in tmp_dic:                    tmp_dic[s[start]] = tmp_dic[s[start]] - 1                start = start + 1        if res_start == -1:            return ""        return s[res_start:res_start+ans]

滑动窗口思想非常经典