Compilare: user.cpp: In function ‘void elimina(int, int)’: user.cpp:23:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < G[v].size(); ++i){ ^ user.cpp: In function ‘void dfs(int)’: user.cpp:33:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < G[nod].size(); ++i){ ^ user.cpp: In function ‘void query()’: user.cpp:40:43: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d",&n,&r[1],&r[2],&r[3]); ^ user.cpp:45:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^ user.cpp: In function ‘int main()’: user.cpp:88:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbxyz.in","r",stdin); ^ user.cpp:89:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbxyz.out","w",stdout); ^ user.cpp:90:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&t); ^