练习了BigInteger的使用的方法, 代码如下:
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) { // 满足条件 1、num为小于1000的正数 2、num为奇数 3、num个位不是5 while( true) { if(bigNum.mod(intToBig).intValue() != 0) { // 111不能整除输入的数 bigNum = bigNum.multiply(BigInteger.valueOf(10)); bigNum = bigNum.add(BigInteger.valueOf(1)); index++; } else { System.out.print(bigNum.divide(intToBig) + " " + index); return; } } } else { return; } } }