def minWindow(s: str, t: str) -> str:
        s_hashmap = {}
        t_hashmap = {}
        left, right = 0, 0
        min_substring = ' ' * 1001
        if len(s) < len(t):
            return ''
        for c in t:
            if c not in t_hashmap:
                t_hashmap[c] = 1
            else:
                t_hashmap[c] += 1
 
        while right < len(s):
            if s[right] in t_hashmap:
                if s[right] not in s_hashmap:
                    s_hashmap[s[right]] = 1
                else:
                    s_hashmap[s[right]] += 1             
 
            if s_hashmap == t_hashmap:
                if (right - left + 1) < len(min_substring):
                    min_substring = s[left:right+1]
                s_hashmap.clear()
                left = right = left + 1
            else:  
                right += 1
 
        return min_substring
 
print(minWindow("ADOBECODEBANC", "ABC"))# your code goes here

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