Compilare: user.cpp: In function ‘bool is_ok(long long int)’: user.cpp:9:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<=n) ^ user.cpp:12:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<=n && v[i]-st<=d) ^ user.cpp:17:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<=n && v[i]-st<=d) ^ user.cpp:20:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(ap<=k) ^ user.cpp: In function ‘int main()’: user.cpp:35:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=2; i<=n; i++) ^ user.cpp:31:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("orase1.in","r",stdin); ^ user.cpp:32:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("orase1.out","w",stdout); ^ user.cpp:34:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&k); ^ user.cpp:37:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&v[i]); ^