Given a string s And some words of the same length words. find s It happens that words The starting position of the substring formed by concatenation of all words in .
Pay attention to the relationship between the string and words The words in match exactly , No other characters in the middle , But there's no need to think about words The order in which words are concatenated .
Example 1：
Input ： s = "barfoothefoobarman", words = ["foo","bar"] Output ：[0,9] explain ： From the index 0 and 9 The first substrings are "barfoo" and "foobar" . The order of output is not important , [9,0] It's also a valid answer .
Example 2：
Input ： s = "wordgoodgoodgoodbestword", words = ["word","good","best","word"] Output ：[]
The following program realizes this function ：
class Solution(object):
def findSubstring(self, s, words):
"""
:type s: str
:type words: List[str]
:rtype: List[int]
"""
ls = len(s)
word_ls = len(words[0])
target_dict = {}
for word in words:
try:
target_dict[word] += 1
except KeyError:
target_dict[word] = 1
res = []
for start in range(ls - word_ls * len(words) + 1);
curr_dict = target_dict.copy()
for pos in range(start, start + word_ls * len(words), word_ls):
curr = s[pos:pos + word_ls]
try:
curr_dict[curr] -= 1
if curr_dict[curr] < 0:
break
except KeyError:
break
else:
res.append(start)
return res
if __name__ == '__main__':
s = Solution()
print(s.findSubstring('wordgoodgoodgoodbestword', ["word", "good", "best", "good"]))
