백준 1427번: 소트인사이드

문제 출처: https://www.acmicpc.net/problem/1427

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.Comparator;
 
public class Main {
    public static void main(String[] args) throws Exception {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        String N = reader.readLine();
        String[] arr = new String[N.length()];
        
        for(int i=0 ; i<arr.length ; i++)
            arr[i] = ""+N.charAt(i);
        
        Arrays.sort(arr, new Comparator<String>() {
            @Override
            public int compare(String o1, String o2) {
                return o2.compareTo(o1);   // string으로 내림차순하기
            }
        });
        
        StringBuilder builder = new StringBuilder();
        for(int i=0 ; i<arr.length ; i++)
            builder.append(arr[i]);
        
        System.out.println(builder);
    }
}