Any Base Multiplication

1. You are given a base b.
2. You are given two numbers n1 and n2 of base b.
3. You are required to multiply n1 and n2 and print the value.

Input Format

A base b
A number n1
A number n2

Output Format

A number of base b equal in value to n2 * n1.

Constraints
2 <= b <= 10
0 <= n1 <= 10000
0 <= n2 <= 10000
Sample Input
5
1220
31
Sample Output
43320

Solution:

import java.util.*;

public class Main{

public static void main(String[] args) {
    Scanner scn = new Scanner(System.in);
    int b = scn.nextInt();
    int n1 = scn.nextInt();
    int n2 = scn.nextInt();

    int d = getProduct(b, n1, n2);
    System.out.println(d);
 }

 public static int getProduct(int b, int n1, int n2){
     // write your code here
     int res = 0, pow = 1;
     
     while(n2 > 0){
         int d2 = n2%10;
         n2 = n2/10;
         
         int sdp = productBySingleDigit(n1,d2,b);
         res = addNumber(res,sdp*pow,b);
         pow*=10;
     }
     
     return res;
 }
 
 public static int productBySingleDigit(int n1,int d2,int b){
     int res = 0, pow =1, c = 0;
     
     while(n1 > 0 || c > 0){
         int d1 = n1%10;
         n1/=10;
         
         int d = (d1 * d2) + c;
         c = d/b;
         res += (d%b) * pow;
         pow*= 10;
     }
     
     return res;
 }

 public static int addNumber(int n1,int n2,int b){
     int res = 0,pow =1,c=0;
     
     while(n1 > 0 || n2 > 0 || c > 0){
         int d1 = n1%10;
         n1/=10;
         int d2 = n2%10;
         n2/=10;
         
         int d = d1 + d2 + c;
         c = d/b;
         res += (d%b)*pow;
         pow*=10;
     }
     
     return res;
 }
}