POJ1426——BFS——Find The Multiple

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