题目：
题解：
class Solution:
def findSubstring(self, s: str, words: List[str]) -> List[int]:
res = []
m, n, ls = len(words), len(words[0]), len(s)
for i in range(n):
if i + m * n > ls:
break
differ = Counter()
for j in range(m):
word = s[i + j * n: i + (j + 1) * n]
differ[word] += 1
for word in words:
differ[word] -= 1
if differ[word] == 0:
del differ[word]
for start in range(i, ls - m * n + 1, n):
if start != i:
word = s[start + (m - 1) * n: start + m * n]
differ[word] += 1
if differ[word] == 0:
del differ[word]
word = s[start - n: start]
differ[word] -= 1
if differ[word] == 0:
del differ[word]
if len(differ) == 0:
res.append(start)
return res
