Compilare: user.cpp: In function ‘std::vector<int, std::allocator<int> > prefix(const std::string&)’: user.cpp:14: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘std::vector<int, std::allocator<int> > match(const std::string&, const std::string&)’: user.cpp:32: warning: comparison between signed and unsigned integer expressions user.cpp:38: warning: comparison between signed and unsigned integer expressions