Compilare: main.cpp: In function 'std::vector<int> Z(std::__cxx11::string, const string&)': main.cpp:15:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < s.size(); ++i) ~~^~~~~~~~~~ main.cpp:19:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i + z[i] < s.size() && s[i + z[i]] == s[z[i]]) ~~~~~~~~~^~~~~~~~~~ main.cpp:28:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < ret.size(); ++i) ~~^~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:50:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < a.size(); ++i) ~~^~~~~~~~~~