题目：

题解：

class Solution {
public:vector<int> findSubstring(string &s, vector<string> &words) {vector<int> res;int m = words.size(), n = words[0].size(), ls = s.size();for (int i = 0; i < n && i + m * n <= ls; ++i) {unordered_map<string, int> differ;for (int j = 0; j < m; ++j) {++differ[s.substr(i + j * n, n)];}for (string &word: words) {if (--differ[word] == 0) {differ.erase(word);}}for (int start = i; start < ls - m * n + 1; start += n) {if (start != i) {string word = s.substr(start + (m - 1) * n, n);if (++differ[word] == 0) {differ.erase(word);}word = s.substr(start - n, n);if (--differ[word] == 0) {differ.erase(word);}}if (differ.empty()) {res.emplace_back(start);}}}return res;}
};