Compilare: user.cpp: In function ‘void DFS(int, int)’: user.cpp:94:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < L[node].size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:155:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = 0; k < niv[j].size(); k++) { ^ user.cpp: In constructor ‘InputReader::InputReader(const char*)’: user.cpp:9:37: 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, input_file); ^ user.cpp: In member function ‘void InputReader::advance()’: user.cpp:31:38: 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, input_file); ^