Compilare: user.cpp: In function ‘std::vector<int> Kmp(const string&)’: user.cpp:16:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < that.size(); ++i) { ^ user.cpp: In function ‘int main()’: user.cpp:38:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = a.size(); i < s.size(); ++i) { ^ user.cpp:39:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (pi[i] == a.size() - 1 and match.size() + 1 <= 1000) { ^