import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.math.BigDecimal;
import java.util.StringTokenizer;

public class Main
{
    public static void main (String args[]) throws Exception
    {
    	BigDecimal big,result,one;
    	int k;
    	byte[] rebyte;
    	one=new BigDecimal("1");
    	String line;
        BufferedReader stdin =
            new BufferedReader(
                new InputStreamReader(System.in));
        while(true)
        {
            line=stdin.readLine();
            if(line==null) break;
            StringTokenizer st = new StringTokenizer(line);
            String a = (st.nextToken());
            int b = Integer.parseInt(st.nextToken());
            big = new BigDecimal(a);
            result=new BigDecimal("1");
            for(int i=0;i<b;i++)
            	result=result.multiply(big);
            String re=result.toString();
            rebyte=re.getBytes();
            for(int i=0;i<rebyte.length;i++)
               rebyte[i]-=48;
            int i=0;
            while(rebyte[i]==0)
            {
                rebyte[i++]=-1;
            }
            i=rebyte.length-1;
            while(rebyte[i]==0)
            {
                rebyte[i--]=-1;
            }
            if(rebyte[i]==-2)
                rebyte[i]=-1;
            for(i=0;i<rebyte.length;i++)
            {
                if(rebyte[i]==-2)
                {
                    System.out.print('.');
                }else if(rebyte[i]==-1)
                {
                }else
                {
                    System.out.print(rebyte[i]);
                }
            }
            System.out.println();

        }
    }
}

• PKU用的是JDK1.5，1.5里BigDecimal的toString()和1.4的返回值不一样，查一下API手册吧 (1859) FinalLaugh 2005-05-24 12:18:16