Envío 6217

Código

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String largeNumber1 = scanner.nextLine();
        String largeNumber2 = scanner.nextLine();
        char[] numberArray1 = largeNumber1.length() >= largeNumber2.length() ? largeNumber1.toCharArray() : largeNumber2.toCharArray();
        char[] numberArray2 = largeNumber1.length() >= largeNumber2.length() ? largeNumber2.toCharArray() : largeNumber1.toCharArray();

        int remain = 0;

        for(int i=numberArray1.length-1, j=numberArray2.length-1; i>=0; i--, j--){
            int number = convertCharToInt(numberArray1[i]);
            int numberToAdd = j >= 0 ? convertCharToInt(numberArray2[j]) : 0;

            int sum = number + numberToAdd + remain;
            if(sum >= 10){
                int newNumber = sum - 10;
                numberArray1[i] = convertIntToChar(newNumber);
                remain = 1;
            } else {
                numberArray1[i] = convertIntToChar(sum);
                remain = 0;
            }
        }

        if(remain == 1){
            System.out.print(1);
        }
        for(int i=0; i<numberArray1.length; i++){
            System.out.print(numberArray1[i]);
        }

    }

    private static int convertCharToInt(char c){
        switch (c){
            case '0': return 0;
            case '1': return 1;
            case '2': return 2;
            case '3': return 3;
            case '4': return 4;
            case '5': return 5;
            case '6': return 6;
            case '7': return 7;
            case '8': return 8;
            case '9': return 9;
            default:
                System.out.println("NOT GOOD"); return -1;
        }
    }

    private static char convertIntToChar(int x){
        switch (x){
            case 0: return '0';
            case 1: return '1';
            case 2: return '2';
            case 3: return '3';
            case 4: return '4';
            case 5: return '5';
            case 6: return '6';
            case 7: return '7';
            case 8: return '8';
            case 9: return '9';
            default:
                System.out.println("NOT GOOD"); return 'n';
        }
    }
}