Why I get WA,here is my code
Послано
final 12 фев 2002 21:06
#include <iostream.h>
#include <math.h>
const double pi=3.1415926;
void main()
{
double x1,y1,bx,by,nx,ny,r;
int n;
cin>>n>>r;
cin>>x1>>y1;
bx=x1;
by=y1;
double ans=0,dis;
for(int i=2;i<=n;i++)
{
cin>>nx>>ny;
dis=sqrt( bx-nx)*(bx-nx)+(by-ny)*(by-ny) );
ans=ans+dis;
bx=nx;
by=ny;
}
if(n>1)
{ ans=ans+sqrt( (nx-x1)*(nx-x1)+(ny-y1)*(ny-y1) ); }
ans=ans+2*pi*r;
cout.precision(2);
cout<<ans<<endl;
}