HDoj2114 大数

import java.util.Scanner;
import java.math.BigDecimal;
import java.math.BigInteger;
public class Main                          //公式 f(n)=(1+2+3+...+n)^2  自己去试几组就行了
{
public static void main(String[]args)
{
Scanner cin=new Scanner(System.in);
while(cin.hasNextBigInteger())
{
int n;
n=cin.nextInt();
BigInteger a=BigInteger.valueOf(n);
BigInteger b=BigInteger.valueOf(n+1);
a=a.multiply(b);
a=a.divide(BigInteger.valueOf(2));
BigInteger t=a.pow(2).mod(BigInteger.valueOf(10000));
if(t.compareTo(BigInteger.ZERO)>=0&&t.compareTo(BigInteger.valueOf(10))<0)
System.out.println("000"+t);
if(t.compareTo(BigInteger.valueOf(10))>=0&&t.compareTo(BigInteger.valueOf(100))<0)
System.out.println("00"+t);
if(t.compareTo(BigInteger.valueOf(100))>=0&&t.compareTo(BigInteger.valueOf(1000))<0)
System.out.println("0"+t);
if(t.compareTo(BigInteger.valueOf(1000))>=0)
System.out.println(t);

//System.out.println(a.pow(2)+":"+t);

}
}
}