백준 자바 11720 문자열(숫자의합)

https://www.acmicpc.net/problem/11720

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        int N = Integer.parseInt(br.readLine());
        String digit = br.readLine();
        char[] arr = digit.toCharArray();
        int sum = 0;

        for(int i=0; i<N;i++){
            sum += arr[i] - '0' ;
        }
        System.out.println(sum);
    }
}