#include <stdio.h>
#include <math.h>
int main(){

freopen("b.in","r",stdin);
freopen("b.out","w",stdout);
double x[102],y[102];
double d1,d2;
int i,star=0,k,m,n,j;
double s,r,pi=2*acos(0);

scanf("%d",&k);

for(m=0;m<k;m++){
    s=0;
scanf("%d %Lf",&n,&r);

for(i=0;i<n;i++)
scanf("%Lf %Lf \n",&x[i],&y[i]);
for(j=0;j<n-1;j++){
    d1=abs(x[j]-x[j+1]);
d2=abs(y[j]-y[j+1]);
s=s+sqrt(d1*d1 + d2*d2);

}
  d1=abs(x[0]-x[n-1]);
d2=abs(y[0]-y[n-1]);
s=s+sqrt(d1*d1 + d2*d2);

s=s+(n*pi*r)/2;

if(star==0) star=1;
else printf("\n");
printf("%.2Lf",s);
}
return 0;
}

#include <iostream>
#include <cmath>
using namespace std;
int main(){
    double PI=acos(-1.0);
    int N; double r(0), perimeter(0);
    cin>>N>>r;
    double *pointx, *pointy;
    pointx = new double[N+1];
    pointy = new double[N+1];
    for(int a=0; a<N; a++){
            cin>>pointx[a]>>pointy[a];
        }
    pointy[N]= pointx[0];
    pointx[N] = pointy[0];
    cout.setf(ios::fixed);
    cout.setf(ios::showpoint);
    cout.precision(2);
    if(N==1){
        perimeter=2*PI*r;
        cout<<perimeter;

        }
    else{
    if(N==2){
        perimeter=2*(pow((pow((pointx[0]-pointx[1]),2)+pow((pointy[0]-pointy[1]),2)),0.5)) + 2*PI*r;
        cout<<perimeter;

    }
    else{
        double angle(0);
        for(int a=0; a<N; a++){
            perimeter += pow((pow((pointx[a]-pointx[a+1]),2)+pow((pointy[a]-pointy[a+1]),2)),0.5);
                }

            double p1x, p2x, p3x, p1y, p2y, p3y, m1, m2;

            p1x=pointx[N-1]; p2x=pointx[0]; p3x=pointx[1];
            p1y=pointy[N-1]; p2y=pointy[0]; p3y=pointy[1];
            if(p3x==p2x)
                m1=tan(PI/2.0);
            if(p2x==p1x)
                m2=tan(PI/2.0);
            if(p2x!=p3x)
                m1=(p3y-p2y)/(p3x-p2x);
            if(p2x!=p1x)
                m2=(p1y-p2y)/(p1x-p2x);
            angle = 2*PI - (PI + fabs(atan(m1)-atan(m2)));
            for(int a=1; a<N; a++){
                p1x=pointx[a-1]; p2x=pointx[a]; p3x=pointx[a+1];
                p1y=pointy[a-1]; p2y=pointy[a]; p3y=pointy[a+1];
            if(p3x==p2x)
                m1=tan(PI/2.0);
            if(p2x==p1x)
                m2=tan(PI/2.0);
            if(p2x!=p3x)
                m1=(p3y-p2y)/(p3x-p2x);
            if(p2x!=p1x)
                m2=(p1y-p2y)/(p1x-p2x);

                angle += ((2*PI) - (PI + fabs(atan(m1)-atan(m2))));
                }

            perimeter += r*angle;
            cout<<perimeter;
            }}
    delete pointx;
    delete pointy;
    return 0;}

// even me wrong answer

Edited by author 13.01.2010 20:27

Edited by author 13.01.2010 20:27