hdu 5109 Alexandra and A*B Problem

#include<iostream>
#include<cstring>
#include<cstdio>
#include<ostream>
#include<istream>
#include<algorithm>
#include<queue>
#include<string>
#include<cmath>
#include<set>
#include<map>
#include<stack>
#include<vector>
#define fi first
#define se second
#define pii pair<int,int>
#define ll long long
#define inf (1ll<<60)
#define eps 1e-8
using namespace std;
const int maxn=210005;
ll a;
char s[100];
ll base[100];
ll ans;
bool work(int c,int len)
{
    int l=strlen(s+1);
    ll Min=inf;
    for(int i=1;i+l-1<=len;i++) {
        for(int j=c;j<base[i-1];j++) {
            ll u=j*base[len-i+1]+ans*base[len-(i+l-1)];
            if(u%a==0)
                Min=min(Min,u);
            else {
                if(a-u%a<base[len-(i+l-1)])
                    Min=min(Min,u+(a-u%a));
            }
        }
    }
    if(Min!=inf) {
        printf("%I64d\n",Min/a);
        return true;
    }
    return false;
}
int main()
{
    base[0]=1;
    for(int i=1;i<=15;i++)
        base[i]=base[i-1]*10;
    while(~scanf("%I64d%s",&a,s+1)) {
        ans=0;
        for(int i=1;i<=strlen(s+1);i++)
            ans=ans*10+s[i]-'0';
        if(s[1]!='0') {
            if(ans%a==0) {
                printf("%I64d\n",ans/a);
                continue;
            }
        }
        for(int i=strlen(s+1)+1;;i++) {
            if(work(s[1]=='0',i))
                break;
        }
    }
    return 0;
}