LeetCode 30.串联所有单词的子串

class Solution:
def findSubstring(self, s: str, words: List[str]) -> List[int]:
    wl=len(words[0]) # word length
    ans=[]
    for offset in range(wl):
        i=offset
        mp=Counter(words)
        for j in range(offset+wl,len(s)+1,wl):
            word=s[j-wl:j]
            if word in mp:
                mp[word]-=1
                while mp[word]<0:
                    i+=wl
                    word_del=s[i-wl:i]
                    mp[word_del]+=1
            else:
                i=j
                mp=Counter(words)
            if sum([v for k,v in mp.items()])==0:
                ans.append(i)
    return ans