Compilare: user.cpp: In function ‘long long int rebuild(std::vector<Edge>&, Edge, int)’: user.cpp:83:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (v == edges.size()) { ^ user.cpp: In constructor ‘InputReader::InputReader(const char*)’: user.cpp:180:37: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, SIZE, 1, file); ^ user.cpp: In member function ‘void InputReader::advance()’: user.cpp:172:41: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, SIZE, 1, file); ^