Poj Solution 2539

http://poj.org/problem?id=2539

//* @author: ccQ.SuperSupper
import java.io.*;
import java.util.*;
import java.math.*;
public class Main {
 static BigInteger digit100=new BigInteger("1");
 static int t,a,b;
 static void start(){
    for(int i=0;i< 100;++i)
        digit100 = digit100.multiply(BigInteger.valueOf(10));
 }

 public static void main(String[]args) throws Exception{

  BigInteger num1,num2,temp,ans;
  start();
  //Scanner cin = new Scanner(new FileInputStream("input.txt"));
  Scanner cin = new Scanner(System.in);
        
  while(cin.hasNext()){
    t = cin.nextInt();
    a = cin.nextInt();
    b = cin.nextInt();
    if((t==1||b==0||a< b)){
        output(BigInteger.valueOf(-1));
    }
    else if(a==0){
        output(BigInteger.valueOf(0));
    }
    else if(a==b){
        output(BigInteger.valueOf(1));
    }
    else if(a%b!=0||(a-b)*java.lang.Math.log10((double)t)>120){
        output(BigInteger.valueOf(-1));
    }
    else{
        temp = BigInteger.valueOf(t);
        num1 = temp.pow(a);
        num2 = temp.pow(b);
        num1 = num1.subtract(BigInteger.ONE);
        num2 = num2.subtract(BigInteger.ONE);
        ans = num1.divide(num2);
        if(ans.toString().length()< 100){
            output(ans);
        }else{
            output(BigInteger.valueOf(-1));
        }
    }
   }
 }

 static void output(BigInteger who){
  if(who.equals(BigInteger.valueOf(-1))){
   System.out.println("("+t+"^"+a+"-1)/("+t+"^"+b+"-1) is not an integer with less than 100 digits.");
  }
  else{
   System.out.println("("+t+"^"+a+"-1)/("+t+"^"+b+"-1) "+who);
  }
 }
}