Envío 7091

Código

import java.util.Scanner;

public class Main{
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        StringBuilder num1 = new StringBuilder(scanner.nextLine()).reverse();
        int digit = scanner.nextInt();
        int n = num1.length();

        for (int i = 0; i < n; i++) {
            int sum = Character.getNumericValue(num1.charAt(i)) + digit;

            if(sum < 10){
                num1.setCharAt(i, (char)(sum + '0'));
                break;
            }else{
                digit = 1;
                num1.setCharAt(i, (char)((sum % 10) + '0'));
            }

            if((i == n - 1) && digit == 1){
                num1.append('1');
            }
        }

        System.out.print(num1.reverse());

        scanner.close();
    }
}