题解

#include<iostream>
using namespace std;
long long ans[1000006];
long long a,b,n,c,d;
int main()
{

cin>>c;
for(long long i=1;i<=c;i++)
{
    cin>>n>>a>>b;
    d=n-1;
    if(a>=b)
    {if(n%2==0) ans[i]=b*n/2;
     else
     {
         ans[i]+=b*(d/2);
         ans[i]+=a;
     }
    } 
    if(a<=b)
    {
        if(b<=2*a)
        {
            if(n%2==0) ans[i]=b*n/2;
            else ans[i]=b*d/2+a;
            
        }
        else ans[i]=a*n;
    }
    cout<<ans[i]<<endl;
}
return 0;

}