NYOJ 大数类总结（java）

3
1
2
3

1
5
21

代码如下：

import java.io.*;
import java.util.*;
import java.math.BigDecimal;
import java.math.BigInteger;//声明BigInteger大数类
public class Main
{
    public static void main(String args[])
    {
        Scanner cin = new Scanner(System.in);
        int t=cin.nextInt();
        while(t-->0)
        {
        	int n;
        	n=cin.nextInt();
        	BigInteger a=BigInteger.valueOf(4);
        	for(int i=1; i<n; ++i)
        		a=a.multiply(BigInteger.valueOf(4));
        	System.out.println(a.subtract(BigInteger.valueOf(1)).divide(BigInteger.valueOf(3)));
        }
    }
}

比较大小

题目链接：http://acm.nyist.net/JudgeOnline/problem.php?pid=73

111111111111111111111111111 88888888888888888888
-1111111111111111111111111  22222222
0 0

a>b
a<b

代码如下：

import java.io.*;
import java.util.*;
import java.math.BigDecimal;
import java.math.BigInteger;//声明BigInteger大数类
public class Main
{
    public static void main(String args[])
    {
        Scanner cin = new Scanner(System.in);
        while(cin.hasNext())
        {
        	BigInteger a=cin.nextBigInteger();
        	BigInteger b=cin.nextBigInteger();
        	BigInteger zero=BigInteger.ZERO;
        	if(a.compareTo(zero)==0&&b.compareTo(zero)==0) break;
        	int f=a.compareTo(b);
        	if(f==-1)
        		System.out.println("a<b");
        	else if(f==0)
        		System.out.println("a==b");
        	else 
        		System.out.println("a>b");
        }
    }
}

递推求值

题目链接：http://acm.nyist.net/JudgeOnline/problem.php?pid=114

1 1 1

69087442470169316923566147

代码如下：

import java.io.*;
import java.util.*;
import java.math.BigDecimal;
import java.math.BigInteger;//声明BigInteger大数类
public class Main
{
    public static void main(String args[])
    {
        Scanner cin = new Scanner(System.in);
        BigInteger fac[]=new BigInteger[100];
        while(cin.hasNext())
        {
        	for(int i=0; i<=2; ++i)
        		fac[i]=cin.nextBigInteger();
        	for(int i=3; i<=99; ++i)
        		fac[i]=fac[i-1].add(fac[i-2]).add(fac[i-3]);
        	System.out.println(fac[99]);
        }
    }
}