java 大数

题目 http://acm.nyist.net/JudgeOnline/status.php?do=search&pid=&userid=wsp&language=0&result=0

 
import java.math.BigInteger;

import java.util.Scanner;

public class Main{

/**
* @param args
*/
public static void main(String[] args) {
Scanner ss=new Scanner(System.in);
int n=ss.nextInt();
while(n-->0)
{
BigInteger ans=new BigInteger("4");
int m;
m=ss.nextInt();
//System.out.println(m);
for(int i=1;i<m;++i)
ans=ans.multiply(BigInteger.valueOf(4));
//ans.multiply(BigInteger.valueOf(4));
//System.out.println(ans);
System.out.println(ans.subtract(BigInteger.valueOf(1)).divide(BigInteger.valueOf(3)));
}
}

} http://acm.nyist.net/JudgeOnline/problem.php?pid=28 
import java.math.BigInteger;
import java.util.Scanner;

public class Main{

/**
* @param args
*/
public static void main(String[] args) {
Scanner ss=new Scanner(System.in);
int n=ss.nextInt();
BigInteger ans=BigInteger.ONE;
for(int i=1;i<=n;i++)
{
ans=ans.multiply(BigInteger.valueOf(i));
}
System.out.println(ans);
}

} http://acm.nyist.net/JudgeOnline/problem.php?pid=114 
import java.io.*;
import java.math.BigInteger;
import java.util.*;

public class Main
{
public static void main(String args[])
{
Scanner cin = new Scanner(System.in);
BigInteger a[] = new BigInteger[100];
while(cin.hasNext())
{
for(int i = 0; i <= 2; ++i)
a[i] = cin.nextBigInteger();
for(int i = 3; i <= 99; ++i)
a[i] = a[i - 1].add(a[i - 2]).add(a[i - 3]);
System.out.println(a[99]);
}
}
}

高精度幂题目：http://acm.nyist.net/JudgeOnline/problem.php?pid=155

import java.math.BigDecimal;import java.util.Scanner;public class Main{/*** @param args*/public static void main(String[] args) {// TODO Auto-generated method stubScanner ss=new Scanner(System.in);while(ss.hasNext()){BigDecimal s1=ss.nextBigDecimal();BigDecimal s2=s1;int n=ss.nextInt();String res = s1.pow(n).stripTrailingZeros().toPlainString(); //整数去掉小数点和后面的0 topla为避免科学计数法if(res.startsWith("0")) //去掉前导0{res = res.substring(1);  //从第二个数开始返回一个新的字符串}System.out.println(res);}}}