Compilare: main.cpp:2:265: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type] 2 | using namespace std;int N=1e5,t,n,i,o,r;void _(auto&a,int q=0){auto b=a;for(r=n=a.size();r/=2;){for(i=0;i<n/2;i+=r){auto w=pow(M_E,(q?-i:i)*M_PI/n*2.0i);for(o=0;o<r;++o){auto u=a[i*2+o],v=w*a[i*2+o+r];b[i+o]=u+v;b[i+n/2+o]=u-v;}}swap(a,b);}if(q)for(auto&x:a)x/=n;}main(){fstream g("bacterii2.in");ofstream l("bacterii2.out");g>>t;while(t--){vector p(N,0i),q=p;g>>n;while(n--)g>>r,p[r]+=1;g>>o;for(;o--;)g>>r,q[r]+=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])+.5;if(o)l<<i<<" "<<o<<'\n';}l<<'\n';}} | ^~~~