Compilare: user.cpp: In function ‘std::pair<int, int> ChainEndNodes(int)’: user.cpp:148:9: warning: variable ‘last_k’ set but not used [-Wunused-but-set-variable] int last_k = x, last_nd = x, last_2 = x; ^ user.cpp: In function ‘std::pair<int, int> DistanceDNodes(int, int)’: user.cpp:268:9: warning: variable ‘last_k’ set but not used [-Wunused-but-set-variable] int last_k = x, last_nd = x, last_2 = x; ^ user.cpp: In function ‘int main()’: user.cpp:424:9: warning: unused variable ‘i’ [-Wunused-variable] int i, j, op, x, y, D; ^ user.cpp:424:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j, op, x, y, D; ^ user.cpp: In constructor ‘InputReader::InputReader(const char*)’: user.cpp:19:48: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, BUFFER_SIZE, 1, file); ^ user.cpp: In member function ‘void InputReader::advance()’: user.cpp:46:52: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, BUFFER_SIZE, 1, file); ^