Find The Multiple

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <queue>
 4 #define ll long long
 5 using namespace std;
 6 void bfs(int n)
 7 {
 8     queue<ll>q;
 9     q.push(1);
10     while(!q.empty())
11     {
12         int i;
13         ll x;
14         x=q.front();
15         q.pop();
16         if(!(x%n))
17         {
18             printf("%lld\n",x);
19             return ;
20         }
21         q.push(x*10);
22         q.push(x*10+1);
23     }
24 }
25 int main()
26 {
27     int n;
28     while(scanf("%d",&n))
29     {
30         if(!n) break;
31         else bfs(n);
32     }
33     return 0;
34 }