pku1001_exponentiation.java

来自「这是本人在北京大学网站上做过的一道题希望对大家有所帮助」· Java 代码 · 共 91 行

/**
 * Exponentiation 
Time Limit:500MS  Memory Limit:10000K
Total Submit:16443 Accepted:3695 

Description
Problems involving the computation of exact values of very large magnitude and precision are common. For example, the computation of the national debt is a taxing experience for many computer systems. 

This problem requires that you write a program to compute the exact value of Rn where R is a real number ( 0.0 < R < 99.999 ) and n is an integer such that 0 < n <= 25. 

Input
The input will consist of a set of pairs of values for R and n. The R value will occupy columns 1 through 6, and the n value will be in columns 8 and 9.

Output
The output will consist of one line for each line of input giving the exact value of R^n. Leading zeros should be suppressed in the output. Insignificant trailing zeros must not be printed. Don't print the decimal point if the result is an integer.

Sample Input


95.123 12
0.4321 20
5.1234 15
6.7592  9
98.999 10
1.0100 12


Sample Output


548815620517731830194541.899025343415715973535967221869852721
.00000005148554641076956121994511276767154838481760200726351203835429763013462401
43992025569.928573701266488041146654993318703707511666295476720493953024
29448126.764121021618164430206909037173276672
90429072743629540498.107596019456651774561044010001
1.126825030131969720661201

Hint
If you don't know how to determine wheather encounted the end of input: 
s is a string and n is an integer 


C++
while(cin>>s>>n)
{
...
}
c
while(scanf("%s%d",s,&n)==2) //to  see if the scanf read in as many items as you want
{
...
}

Source
East Central North America 1988

 */

import java.math.BigDecimal;
import java.util.Scanner;
import java.math.RoundingMode;
/**
 * @author nyz
 * @version 1.0 06/11/22
 */
public class Main {

	public static void main(String[] args) {
		Scanner scan=new Scanner(System.in);
		String r;
		int n;
		BigDecimal R;
		while (scan.hasNext()) {			
			R=scan.nextBigDecimal();
			n = scan.nextInt();			
			// R.setScale(5,RoundingMode.HALF_EVEN);
			BigDecimal result=R.pow(n);
			// System.out.println(R);
			// System.out.println(R.scale());
			String output=result.stripTrailingZeros().toPlainString();
			if(output.charAt(0)=='0'){
				int i=0;
				while(output.charAt(i)=='0')
					i++;
				output=output.substring(i);
			}
			System.out.println(output);
		}
	}
}