Compilare: main.cpp:2:285: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type] 2 | using namespace std;const int N=1<<16;int t,n,x,i,o,m,r,j;void _(auto&a,int q=0){n=a.size();auto b=a;for(r=n;r/=2;){for(i=0;i<n/2;i+=r){auto w=pow(M_E,(q?-i:i)*M_PI/n*2.0i);for(j=0;j<r;++j){auto u=a[i*2+j],v=w*a[i*2+j+r];b[i+j]=u+v;b[i+n/2+j]=u-v;}}swap(a,b);}if(q)for(auto&x:a)x/=n;}main(){ifstream g("bacterii2.in");ofstream l("bacterii2.out");g>>t;while(t--){vector<complex<double>>p(N),q=p;g>>n;while(n--)g>>x,p[x]+=1;g>>m;for(;m--;)g>>x,q[x]+=1;_(p);_(q);for(i=0;i<N;++i)p[i]*=q[i];_(p,1);for(i=0;i<N;++i){o=real(p[i])+0.5;if(o>0)l<<i<<" "<<o<<'\n';}l<<'\n';}} | ^~~~