Poj Solution 2546

http://poj.org/problem?id=2546

//* @author: ccQ.SuperSupper
import java.io.*;
import java.text.DecimalFormat;
import java.util.*;
import java.math.*;
public class Main {

    /**
     * @param args
     */
    static double min(double a,double b)
    {
        if(a>b) return b;
        return a;
    }
    static double max(double a,double b)
    {
        if(a>b) return a;
        return b;
    }
    public static double Number3(double pDouble)
    {
        String pattern = "##0.###";
        DecimalFormat df = new DecimalFormat(pattern);
        String result = String.valueOf(df.format(pDouble));
        System.out.println(result);
        pDouble = Double.parseDouble(result);
        return pDouble;
    }
    
  public static void main(String[] args)throws Exception {
   // TODO Auto-generated method stub
   double x1,y1,r1,x2,y2,r2,disten,ans;
        
   Scanner cin = new Scanner(System.in);
   while(cin.hasNext()){
    x1 = cin.nextDouble();
    y1 = cin.nextDouble();
    r1 = cin.nextDouble();
        
    x2 = cin.nextDouble();
    y2 = cin.nextDouble();
    r2 = cin.nextDouble();
        
    disten = Math.sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));
            
    if(disten>=r1+r2){
        ans = 0.0;
    }
    else if(disten+min(r1,r2)<=max(r1,r2)){
        ans = Math.acos(-1) * min(r1,r2) * min(r1,r2);
    }
    else
    {
    double ans1,ans2;
 ans1 = Math.acos((min(r1,r2)*min(r1,r2)+disten*disten-max(r1,r2)*max(r1,r2))/2.0/min(r1,r2)/disten);
 ans2 = Math.acos((max(r1,r2)*max(r1,r2)+disten*disten-min(r1,r2)*min(r1,r2))/2.0/max(r1,r2)/disten);
        ans = (r1+r2+disten)/2.0;
    ans = Math.sqrt(ans*(ans-r1)*(ans-r2)*(ans-disten));
    ans = max(r1,r2)*max(r1,r2)*ans2 + min(r1,r2)*min(r1,r2)*ans1 - 2.0*ans;
    }
    //    ans = Math.floor(ans*1000+0.5)/1000;
            
    DecimalFormat df = new DecimalFormat("##0.000");
    System.out.println(df.format(ans));
   }
}

}