[java 백준] 브론즈 2/ 2745번 진법 변환

https://www.acmicpc.net/problem/2745

2745번: 진법 변환

import java.io.IOException;
import java.util.Scanner;
 
public class Main {
 
    public static void main(String[] args) throws IOException {
        Scanner sc = new Scanner(System.in);
 
        StringBuilder sb = new StringBuilder();
 
        String s = sc.next();
        int len = s.length();
        int[] arr = new int[len];
        int B = sc.nextInt();
        long total = 0;
 
        for (int j = 0; j < len; j++) {
            if ('A' <= s.charAt(j) && s.charAt(j) <= 'Z') {
                arr[j] = (int) s.charAt(j) - 55;
            } else if ('0' <= s.charAt(j) && s.charAt(j) <= '9') {
                arr[j] = (int) s.charAt(j) - 48;
            }
 
        }
        for (int j = 0; j < len - 1; j++) {
            total = (total + arr[j]) * B;
 
        }
        total += arr[len - 1];
        sb.append(total);
 
        System.out.println(sb.toString());
 
    }
 
}