JAVA大数类练手 - 一路向西去

• Z时代
• 2024-01-10
• 分类：综合

JAVA大数类练手

今天突然看到了OJ上的大数类题目，由于学习了一点大数类的知识。果断水了6道题。。。。。。都是非常基础的。就当的练手的吧。

学到的只是一些大数类的基本操作。以后多做点这样的题，争取熟练运用水大数题。。。

大数阶乘

题目链接：http://acm.nyist.net/JudgeOnline/problem.php?pid=28

代码如下：

[java] view plaincopyprint?

1. import java.io.*; 
2. import java.math.BigInteger; 
3. import java.util.*; 
4.  
5. publicclass Main 
6. { 
7.     publicstaticvoid main(String args[]) 
8.     { 
9.         Scanner cin = new Scanner(System.in);    
10.         int n = cin.nextInt(); 
11.         BigInteger ans = BigInteger.ONE; 
12.         for(int i = 1; i <= n; ++i) 
13.             ans = ans.multiply(BigInteger.valueOf(i)); 
14.         System.out.println(ans); 
15.     } 
16. } 

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);	
		int n = cin.nextInt();
		BigInteger ans = BigInteger.ONE;
		for(int i = 1; i <= n; ++i)
			ans = ans.multiply(BigInteger.valueOf(i));
		System.out.println(ans);
	}
}

棋盘覆盖

题目链接：http://acm.nyist.net/JudgeOnline/problem.php?pid=45

代码如下：

[java] view plaincopyprint?

1. import java.math.BigInteger; 
2. import java.util.*; 
3. import java.io.*; 
4.  
5. publicclass Main 
6. { 
7.     publicstaticvoid main(String args[]) 
8.     { 
9.         Scanner in = new Scanner(System.in); 
10.         int test = in.nextInt(); 
11.         while(test-- > 0) 
12.         { 
13.             int n; 
14.             n = in.nextInt(); 
15.             BigInteger a = new BigInteger("4"); 
16.             for(int i = 1; i < n; ++i) 
17.                 a = a.multiply(BigInteger.valueOf(4)); 
18.             System.out.println(a.subtract(BigInteger.valueOf(1)).divide(BigInteger.valueOf(3))); 
19.         } 
20.     } 
21. } 

import java.math.BigInteger;
import java.util.*;
import java.io.*;
public class Main
{
	public static void main(String args[])
	{
		Scanner in = new Scanner(System.in);
		int test = in.nextInt();
		while(test-- > 0)
		{
			int n;
			n = in.nextInt();
			BigInteger a = new BigInteger("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

代码如下：

[java] view plaincopyprint?

1. import java.io.*; 
2. import java.math.BigInteger; 
3. import java.util.*; 
4.  
5. publicclass Main 
6. { 
7.     publicstaticvoid main(String args[]) 
8.     { 
9.         Scanner cin = new Scanner(System.in);    
10.         while(cin.hasNext()) 
11.         { 
12.             BigInteger a = cin.nextBigInteger(); 
13.             BigInteger b = cin.nextBigInteger(); 
14.             if(a.equals(BigInteger.ZERO) && b.equals(BigInteger.ZERO)) 
15.                 break; 
16.             int flag = a.compareTo(b); 
17.             if(flag == -1) 
18.                 System.out.println("a<b"); 
19.             elseif(flag == 0) 
20.                 System.out.println("a==b"); 
21.             else 
22.                 System.out.println("a>b"); 
23.         } 
24.     } 
25. } 

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);	
		while(cin.hasNext())
		{
			BigInteger a = cin.nextBigInteger();
			BigInteger b = cin.nextBigInteger();
			if(a.equals(BigInteger.ZERO) && b.equals(BigInteger.ZERO))
				break;
			int flag = a.compareTo(b);
			if(flag == -1)
				System.out.println("a<b");
			else if(flag == 0)
				System.out.println("a==b");
			else
				System.out.println("a>b");
		}
	}
}

大数加法

题目链接：http://acm.nyist.net/JudgeOnline/problem.php?pid=103

代码如下：

[java] view plaincopyprint?

1. import java.math.BigInteger; 
2. import java.util.*; 
3. import java.io.*; 
4.  
5. publicclass Main 
6. { 
7.     publicstaticvoid main(String args[]) 
8.     { 
9.         Scanner in = new Scanner(System.in); 
10.         int n = in.nextInt();        
11.         for(int i = 1; i <= n; ++i) 
12.         { 
13.             BigInteger a = in.nextBigInteger(); 
14.             BigInteger b = in.nextBigInteger(); 
15.             BigInteger ans = a.add(b); 
16.             System.out.println("Case " + i + ":"); 
17.             System.out.println(a + " + " + b + " = " +ans); 
18.         } 
19.     } 
20. } 

import java.math.BigInteger;
import java.util.*;
import java.io.*;
public class Main
{
	public static void main(String args[])
	{
		Scanner in = new Scanner(System.in);
		int n = in.nextInt();		
		for(int i = 1; i <= n; ++i)
		{
			BigInteger a = in.nextBigInteger();
			BigInteger b = in.nextBigInteger();
			BigInteger ans = a.add(b);
			System.out.println("Case " + i + ":");
			System.out.println(a + " + " + b + " = " +ans);
		}
	}
}

递推求值

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

代码如下：

[java] view plaincopyprint?

1. import java.io.*; 
2. import java.math.BigInteger; 
3. import java.util.*; 
4.  
5. publicclass Main 
6. { 
7.     publicstaticvoid main(String args[]) 
8.     { 
9.         Scanner cin = new Scanner(System.in);    
10.         BigInteger a[] = new BigInteger[100]; 
11.         while(cin.hasNext()) 
12.         { 
13.             for(int i = 0; i <= 2; ++i) 
14.                 a[i] = cin.nextBigInteger(); 
15.             for(int i = 3; i <= 99; ++i) 
16.                 a[i] = a[i - 1].add(a[i - 2]).add(a[i - 3]); 
17.             System.out.println(a[99]); 
18.         } 
19.     } 
20. } 

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

题目链接：http://acm.nyist.net/JudgeOnline/problem.php?pid=155

代码如下：

[java] view plaincopyprint?

1. import java.io.*; 
2. import java.math.BigDecimal; 
3. import java.util.*; 
4.  
5. publicclass Main 
6. { 
7.     publicstaticvoid main(String args[]) 
8.     { 
9.         Scanner cin = new Scanner(System.in);    
10.         while(cin.hasNext()) 
11.         { 
12.             BigDecimal ans = cin.nextBigDecimal(); 
13.             int n = cin.nextInt(); 
14.             String res = ans.pow(n).stripTrailingZeros().toPlainString(); //整数去掉小数点和后面的0  
15.             if(res.startsWith("0")) //去掉前导0  
16.             { 
17.                 res = res.substring(1); 
18.             } 
19.             System.out.println(res); 
20.         } 
21.     } 
22. } 

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