Java大数-流氓

JAVA 大数类

碰到很多大数类的题目，听说JAVA比较流氓，赶紧去学习一波（ <(▰˘◡˘▰)> ）
 
大数相加：

1 //JAVA 大数相加
2 import java.math.BigInteger;
3 import java.util.*;
4 import java.io.*;
5
6 public class Main
7 {
8     public static void main(String args[])
9     {
10         Scanner cin = new Scanner(System.in);
11             BigInteger a = cin.nextBigInteger();
12             BigInteger b = cin.nextBigInteger();
13             BigInteger ans = a.add(b);
14             System.out.println(ans);
15     }
16 }

 
大数相乘：

1 //JAVA 大数相乘
2 import java.math.BigInteger;
3 import java.util.*;
4 import java.io.*;
5
6 public class Main
7 {
8     public static void main(String args[])
9     {
10         Scanner cin = new Scanner(System.in);
11             BigInteger a = cin.nextBigInteger();
12             BigInteger b = cin.nextBigInteger();
13             BigInteger ans = a.multiply(b);
14             System.out.println(ans);
15     }
16 }

 
大数相减：public BigInteger subtract(BigInteger val)
大数相除：public BigInteger divide(BigInteger val)
 
大数阶乘：

1 //JAVA 大数阶乘
2 import java.io.*;
3 import java.math.BigInteger;
4 import java.util.*;
5
6 public class Main
7 {
8     public static void main(String args[])
9     {
10         Scanner cin = new Scanner(System.in);
11         int n = cin.nextInt(); //输入int型
12         BigInteger ans = BigInteger.ONE;
13         for(int i = 1; i <= n; i++)
14         ans = ans.multiply(BigInteger.valueOf(i));
15         System.out.println(ans);
16     }
17 }

 
大数比较大小

1 //JAVA 大数比较大小
2 import java.io.*;
3 import java.math.BigInteger;
4 import java.util.*;
5
6 public class Main
7 {
8     public static<
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9     {
10         Scanner cin = new Scanner(System.in);
11         while(cin.hasNext())
12         {
13             BigInteger a = cin.nextBigInteger();
14             BigInteger b = cin.nextBigInteger();
15             if(a.equals(BigInteger.ZERO) && b.equals(BigInteger.ZERO)) break;
16             int flag = a.compareTo(b);
17             if(flag == -1)
18                 System.out.println("a<b");
19             else if(flag == 0)
20                 System.out.println("a==b");
21             else
22                 System.out.println("a>b");
23         }
24     }
25 }

 
高精度幂

1 //JAVA 高精度幂
2 import java.io.*;
3 import java.math.BigDecimal;
4 import java.util.*;
5
6 public class Main
7 {
8     public static void main(String args[])
9     {
10         Scanner cin = new Scanner(System.in);
11         while(cin.hasNext())
12         {
13             BigDecimal ans = cin.nextBigDecimal();
14             int n = cin.nextInt();
15             String res = ans.pow(n).stripTrailingZeros().toPlainString(); //整数去掉后面的0和小数点
16             if(res.startsWith("0")) //去掉前导0
17             {
18                 res = res.substring(1);
19             }
20             System.out.println(res);
21         }
22     }
23 }

//这里的BigDecimal相当于double，但是精度更高