Compilare: user.cpp: In function ‘void Prefix(std::string&)’: user.cpp:36:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( size_t i = 1; i < N; ++i ) ^ user.cpp: In function ‘void KMP()’: user.cpp:50:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( size_t i = 0; i < M; ++i ) ^