Compilare: user.cpp: In function ‘void df(int, int)’: user.cpp:20:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<v[x].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:29:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbore3.in","r",stdin); ^ user.cpp:30:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbore3.out","w",stdout); ^ user.cpp:32:37: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d",&n,&s,&a,&d[1]); ^ user.cpp:35:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&a,&d[i]); ^