lyuboyn.cpp:18:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
18 | main(){
| ^
lyuboyn.cpp: In function 'int main()':
lyuboyn.cpp:35:15: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::__cxx11::basic_string<char> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
35 | for (i=0;i<v.size()/2;++i)cout <<v[i]<<"\n";
| ~^~~~~~~~~~~
lyuboyn.cpp:36:24: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::__cxx11::basic_string<char> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
36 | for (i=v.size()-1;i>=v.size()/2;--i)cout <<v[i]<<"\n";
| ~^~~~~~~~~~~~
lyuboyn.cpp:11:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
11 | #define scan3(a,b,c) scanf("%lld %lld %lld",&a,&b,&c);
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
lyuboyn.cpp:20:5: note: in expansion of macro 'scan3'
20 | scan3(n,k,t)
| ^~~~~