//1020. Rope

# include <cstdio>
# include <cmath>
# include <iomanip>
# include <iostream>

using namespace std;

struct dbl{double x,y;};

int n,r;
dbl p[110];
double res;

int main()
{
   cin>>n>>r;

   for(int i=0;i<n;i++)
   cin>>p[i].x>>p[i].y;

   for(int i=1;i<n;i++)
   res+=sqrt( (p[i].x-p[i-1].x)*(p[i].x-p[i-1].x) + (p[i].y-p[i-1].y)*(p[i].y-p[i-1].y) );

   res+=sqrt( (p[0].x-p[n-1].x)*(p[0].x-p[n-1].x) + (p[0].y-p[n-1].y)*(p[0].y-p[n-1].y) );

   res+=2*r*acos(-1.0);

   printf("%.2lf",res);

   return 0;
}

Can you please tell me what is wrong in it?

Edited by author 18.08.2012 05:19

Edited by author 19.08.2012 20:03

You get 2*PI*r when n is 1~
Try the case 1 1!

Edited by author 29.08.2012 15:41

Edited by author 29.08.2012 15:41