Compilare: user.cpp: In function ‘int main()’: user.cpp:61:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<F.size();++i) ^ user.cpp:52:9: warning: unused variable ‘val’ [-Wunused-variable] int val; ^ user.cpp:49:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("catun.in","r",stdin); ^ user.cpp:50:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("catun.out","w",stdout); ^ user.cpp:51:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d",&n,&m,&k); ^ user.cpp:56:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d ",&x); ^ user.cpp:70:35: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d",&x,&y,&z); ^