51nod 1873 初中的算术

BigDecimal大法好

import java.util.*;import java.math.*;public class Main {    public static void main(String[] args) {        Scanner cin = new Scanner(System.in);        String str = cin.next();        int n = cin.nextInt();        BigDecimal res = new BigDecimal(1);        final BigDecimal bd = new BigDecimal(str);        for(int i = 0; i < n; ++i){            res = res.multiply(bd);        }        str = res.stripTrailingZeros().toPlainString();        System.out.println(str.startsWith("0.") ? str.substring(1) : str);    }}