Compilare: user.cpp: In function ‘int VertexCover(int)’: user.cpp:109:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < Vector[nod].size(); i ++){ ^ user.cpp:120:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < Vector[nod].size(); i ++){ ^ user.cpp: In function ‘int main()’: user.cpp:55:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("java.out","w", stdout); ^ user.cpp: In constructor ‘InputReader::InputReader(const char*)’: user.cpp:21:47: 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:43:51: 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); ^