POJ 1426 Find The Multiple

#include <stdio.h>
#include <string.h>
#include <algorithm>
#include <iostream>
#include <queue>
using namespace std;
int n;
void bfs()
{
    queue<long long>q;
    q.push(1);
    while(!q.empty())
    {
        long long a=q.front();
        q.pop();
        if((a*10+1)%n==0)
        {
            cout<<a*10+1<<endl;
            return ;
        }
        q.push(a*10+1);
        if((a*10)%n==0)
        {
            cout<<a*10<<endl;
            return ;
        }
        q.push(a*10);
    }
    return ;
}
int main()
{
    while(~scanf("%d",&n)&&n)
    {
        bfs();
    }
    return 0;
}