Compilare: user.cpp: In function ‘bool VertexCover(int)’: user.cpp:21:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < Vector[nod].size(); i ++){ ^ user.cpp:32:41: 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:48:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("senat.in" ,"r", stdin ); ^ user.cpp:49:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("senat.out","w", stdout); ^ user.cpp:51:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &M, &N); ^ user.cpp:54:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c", &ch); ^ user.cpp:62:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c", &ch); ^