PAT-1010 Radix (25)

#include<stdio.h>
#include<string>
#include<cmath>
#include<iostream>
using namespace std;

int main()
{
  string a,b;
  int tag,radix;
  int anum,bnum;
  //freopen("1010-in.txt","r",stdin);
  //freopen("1010-out.txt","w",stdout);
  
  while(cin>>a>>b>>tag>>radix)
  {
     anum=bnum=0;
     string temp;
     if(tag==1)
     {
        int index=0;
        for(int j=a.length()-1;j>=0;j--)
        {
           anum+=(a[j]>=‘a‘?a[j]-‘a‘+10:a[j]-‘0‘)*pow(radix*1.0,index);
           index++;
        }  
        temp=b;
     }else
     {
        int index=0;
        for(int j=b.length()-1;j>=0;j--)
        {
           anum+=(b[j]>=‘a‘?b[j]-‘a‘+10:b[j]-‘0‘)*pow(radix*1.0,index);
           index++;
        } 
        temp=a;
     }
     //printf("anum=%d\n",anum);  
     char max=0;
     //get max num; 
     for(int i=0;i<temp.length();i++)
     {
       if(temp[i]>max)
         max=temp[i];
     }
     int maxNum=(max>=‘a‘?max-‘a‘+10:max-‘0‘);
     bool flag=false;
     int ind;
     
     //printf("maxNum=%d\n",maxNum);
     long long  maxRadix=0xffffffff;
     maxRadix=maxRadix>>1;
     for(ind=maxNum+1;ind<=maxRadix;ind++)
     {
        bnum=0;
        int index=0;
        for(int j=temp.length()-1;j>=0;j--)
        {
           bnum+=(temp[j]>=‘a‘?temp[j]-‘a‘+10:temp[j]-‘0‘)*pow(ind*1.0,index);
           index++;
        }
        if(bnum>anum)
           break;
        //printf("%d ",bnum);
        if(anum==bnum)
        {
            flag=true;
            break;
        }
     }
     
     if(flag)
     {
        printf("%d\n",ind==1?ind+1:ind);
     }
     else
     {
         printf("Impossible\n");
     }
  }
      
}