練習了BigInteger的使用的方法, 程式碼如下:

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.math.BigInteger;

public class Main {

    public static void main(String[] args) throws Exception{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));        
        BigInteger bigNum 
 
= new BigInteger(String.valueOf(1));
        int index = 1;
        int num = Integer.parseInt(br.readLine());
        BigInteger intToBig = BigInteger.valueOf(num);
        if(num > 0 && num < 1000 && num%2 != 0 && num%5 != 0) {  // 滿足條件 1、num為小於1000的正數 2、num為奇數 3、num個位不是5
            while
 
( true) {
                if(bigNum.mod(intToBig).intValue() != 0) {  // 111不能整除輸入的數
                    bigNum = bigNum.multiply(BigInteger.valueOf(10));
                    bigNum = bigNum.add(BigInteger.valueOf(1));
                    index++;
                } else {
                    System.out.print(bigNum.divide(intToBig) 
 
+ " " + index);
                    return;
                }
            }
        } else {
            return;
        }
        

    }

}