Find the Multiple（java版）

Given a positive integer n, write a program to find out a nonzero multiple m of n whose decimal representation contains only the digits 0 and 1. You may assume that n is not greater than 200 and there is a corresponding m containing no more than 100 decimal digits.

Input

The input file may contain multiple test cases. Each line contains a value of n (1 <= n <= 200). A line containing a zero terminates the input.

Output

For each value of n in the input print a line containing the corresponding value of m. The decimal representation of m must not contain more than 100 digits. If there are multiple solutions for a given value of n, any one of them is acceptable.

Sample Input

2
6
19
0

Sample Output

10
100100100100100100
111111111111111111

dfs 枚举 cur×10和和cur×10+1 即可，long 最长的长度是 19，所以如果位数大于 19 就直接 return 了

import java.util.Scanner;
public class Main {
    static int n;
    static boolean flag;
    static void dfs(int idx,long cur) {//idx当前是几位数，cur当前枚举的数,flag表示找到没有
        if(idx > 19 || flag)
            return;
        if(cur % n == 0) {
            flag = true;
            System.out.println(cur);
            return;
        }
        dfs(idx + 1,cur * 10);
        dfs(idx + 1,cur * 10 + 1);
    }
    public static void main(String[] args) {
        Scanner cin = new Scanner(System.in);
        while(cin.hasNext()) {
            n = cin.nextInt();
            if(n == 0)
                break;
            flag = false;
            dfs(1,1L);
        }
    }
}