题目：

题解：

class Solution {
public:bool kmp(const string& query, const string& pattern) {int n = query.size();int m = pattern.size();vector<int> fail(m, -1);for (int i = 1; i < m; ++i) {int j = fail[i - 1];while (j != -1 && pattern[j + 1] != pattern[i]) {j = fail[j];}if (pattern[j + 1] == pattern[i]) {fail[i] = j + 1;}}int match = -1;for (int i = 1; i < n - 1; ++i) {while (match != -1 && pattern[match + 1] != query[i]) {match = fail[match];}if (pattern[match + 1] == query[i]) {++match;if (match == m - 1) {return true;}}}return false;}bool repeatedSubstringPattern(string s) {return kmp(s + s, s);}
};