【题目描述】

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

【题目分析】
看到这道题的第一反应是好像要用高精度，但是自己高精度又不太熟，所以就上网看了一下题解，发现并不用高精度就可以做出来，应该是数论什么的保证了有正确性或者是数据比较水？
得到的经验就是：看到一道题思考要用可能要用什么算法是对的，但是不能因为局限在这种可能性中停滞不前，可能的话还有不出现的概率呢，先试一下，比赛是即时反馈的，做出来才是王道。

#include<cstdio>
#include<cstring>
#include<queue>
using namespace std;typedef unsigned long long ll;
ll n,flag,t,p;void BFS()
{queue<ll> q;t=1;q.push(t);while(!q.empty()){t=q.front(); q.pop();if(t%n==0){printf("%llu\n",t);return;}p=t*10; q.push(p);p=t*10+1; q.push(p);}
}int main()
{while(~scanf("%d",&n) && n){flag=0;BFS();}return 0;
}