[백준 Java] 약수, 배수와 소수 - 9506번: 약수들의 합

 

 

import java.io.*;
import java.util.ArrayList;
import java.util.StringTokenizer;

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

        while (true) {
            int n = Integer.parseInt(br.readLine());
            if (n == -1) {
                break;
            }

            ArrayList<Integer> div = new ArrayList<>();
            int sum = 0;

            for (int i = 1; i <= n /2; i++){
                if (n % i == 0) {
                    div.add(i);
                    sum += i;
                }
            }

            if (n == sum) {
                bw.write(n + " = " + div.get(0));
                for (int i = 1; i < div.size(); i++) {
                    bw.write(" + " + div.get(i));
                }
                bw.write("\n");
            } else {
                bw.write(n + " is NOT perfect.\n");
            }
        }

        br.close();
        bw.flush();
        bw.close();
    }
}