import java.text.DecimalFormat;
import java.util.Scanner;

public class P1020 {
    private static double pi = 3.14159;
    private static double totalDist;

    public static void main(String args[]) {

        DecimalFormat df = new DecimalFormat("#.##");

        Scanner in = new Scanner(System.in);
        int nRopes = in.nextInt();
        double radius = in.nextDouble();
        double[][] nodes = new double[nRopes][2];

        for (int i=0; i<nRopes; i++) {
            nodes[i][0] = in.nextDouble();
            nodes[i][1] = in.nextDouble();
        }

        totalDist = distance(nodes[0], nodes[nRopes-1])+pi*radius*2;
        for (int i=0; i < nRopes-1; i++) {
            totalDist += distance(nodes[i], nodes[i+1]);
        }

        System.out.println(df.format(totalDist));
    }

    static double distance (double arr1[], double arr2[]) {
        double distance = Math.sqrt((Math.pow((arr1[0]-arr2[0]), 2)+Math.pow((arr1[1]-arr2[1]), 2)));
        return distance;
    }
}

Can you say different between code? I have WA#4

import java.io.PrintWriter;
import java.util.Scanner;


public class p1020 {

    /**
     * @param args
     */
    static double line(double xy, double xy2,double xy3,double xy4){
        return (Math.sqrt(Math.pow(xy-xy3,2)+Math.pow(xy2-xy4,2)));
    }

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner in = new Scanner(System.in);
        PrintWriter out = new PrintWriter(System.out);
        int n = in.nextInt();
        double r = in.nextDouble();
        double pi = 3.14159;
        if (n==1) {
            out.println(Math.round(pi*r*200)/100.00);
            out.flush();
            return;
        }
        float[][] c = new float[n][2];
        for (int i =0; i < n; i++ ){
            c[i][0]=in.nextFloat();
            c[i][1]=in.nextFloat();
        }

        double res = pi *2 *r;
        for (int i =0; i < n-1; i++ ){
            res+=line(c[i][0],c[i+1][0],c[i][1],c[i+1][1]);
        }

        res+=line(c[0][0],c[n-1][0],c[0][1],c[n-1][1]);
        out.println(Math.round(res*100)/100.00);
        out.flush();
    }

}