POJ 1426-Find The Multiple

#include <cstdio>
#include <cmath>
#include <cstring>
#include <string>
#include <algorithm>
#include <queue>
#include <map>
#include <stack>
#include <vector>
#include <iostream>
using namespace std;

int main()
{
int i,j,k;

int n;
while( scanf("%d",&n)!=EOF)
{
if (!n) break;
int all=1<<19;
for (j=all-1;j>=1;j--)
{
int tmp=j;
string sum;
for(i=1;i<=19;i++)
{
sum+='0'+tmp%2;
tmp/=2;
}

__int64 ans=0;
for (i=sum.length()-1;i>=0;i--)
{
ans=ans*10+sum[i]-'0';
}
if (ans%n==0)
{
printf("%I64d\n",ans);
break;
}
}

}
return 0;

}