搜索 H - 08

Description

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

      这为一道DFS题，可以用递归函数循环判断乘以10跟乘10加1的情况，直到找到满足条件的数。

源代码如下：

#include<iostream>
#include<stdio.h>
using namespace std; 
int h;
void DFS(unsigned __int64 m,int n,int k)
{ if(h) return ;
  if(m%n==0)
  { printf("%I64u\n",m);
     h=1;
    return ;
  }
  if(k==19) return ;
  DFS(m*10,n,k+1);
  DFS(m*10+1,n,k+1);
}
int main()
{ int n;
  while(scanf("%d",&n)&&n!=0)
  { 
    h=0;
    DFS(1,n,0);
  }
  return 0;
}