POJ 1001 Exponentiation

最裸的高精度幂，记录一下Java里面高精度类的用法而已

import java.io.*;
import java.util.Scanner;
import java.math.*;

public class Main
{
    public static void main(String[] args)
    {
        Scanner cin = new Scanner(System.in);
        while(cin.hasNext()) {
            int m;
            String sn;
            sn = cin.next();
            m = cin.nextInt();
            BigDecimal n = new BigDecimal(sn);
            String ans = n.pow(m).toPlainString();
            if(ans.charAt(0) != '0') System.out.print(ans.charAt(0)); 
            int len = ans.length();
            while(ans.charAt(len - 1) == '0') len--;
            if(ans.charAt(len - 1) == '.') len--;
            for(int i = 1;i < len;i++) System.out.print(ans.charAt(i));
            if(len == 1 && ans.charAt(0) == '0') System.out.print('0');
            System.out.print('
');
        }
    }
}

其中BigDecimal类的toPlainString方法可以将浮点数转化成精确形式的字符串而不是科学计数法表示