高精度 java的一些题

poj 1001 Exponentiation

import java.util.*;
import java.math.*;
public class Main {
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		while(in.hasNextBigDecimal()) {
			BigDecimal a = in.nextBigDecimal();
			int b = in.nextInt();
			a = a.pow(b);
			a = a.stripTrailingZeros();
			String ans = a.toPlainString();
			if(ans.startsWith("0."))
				ans = ans.substring(1);
			System.out.println(ans);
		}

	}

}

poj 1503 Integer Inquiry

大数加法

```
import java.util.*;
import java.math.*;
public class Main {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
BigInteger a, b, c;
c = BigInteger.valueOf(0);
b = BigInteger.valueOf(0);
while(true) {
a = in.nextBigInteger();
if(a.equals(c))
break;
b = b.add(a);
}
System.out.println(b);
}

}

<h3> <a href = "http://acm.hdu.edu.cn/showproblem.php?pid=1042", target = "_blank">hdu 1042 N! </a> </h3>
<h3> 大数乘法 </h3>

import java.util.;

import java.math.;

public class Main {

public static void main(String[] args) {

Scanner in = new Scanner(System.in);

BigInteger ans, c;

while(in.hasNextInt()) {

int n = in.nextInt();

ans = BigInteger.valueOf(1);

for(int i = n; i >= 1; i--) {

c = BigInteger.valueOf(i);

ans = ans.multiply(c);

}

System.out.println(ans);

}

}

}

<h3> <a href = "http://acm.hdu.edu.cn/showproblem.php?pid=1316", target = "_blank">hdu 1316 How Many Fibs? </a> </h3>
<h3> 大数乘法, 求给出的两个数之间有多少个fib数</h3>

import java.util.;

import java.math.;

public class Main {

public static void main(String[] args) {

Scanner in = new Scanner(System.in);

BigInteger f[] = new BigInteger[505];

f[1] = new BigInteger("1");

f[2] = new BigInteger("2");

for(int i = 3; i<= 500; i++) {

f[i] = f[i-1].add(f[i-2]);

}

BigInteger a, b, zero;

zero = BigInteger.valueOf(0);

while(true) {

a = in.nextBigInteger();

b = in.nextBigInteger();

if(a.equals(zero) && b.equals(zero)) {

break;

}

int tmp = 0;

for(int i = 1; i <= 500; i++) {

if(f[i].compareTo(a)>=0 && f[i].compareTo(b)<=0)

tmp++;

}

System.out.println(tmp);

}

}

}