두 개 뽑아서 더하기

package programmers;

import java.util.Arrays;
import java.util.Iterator;
import java.util.Set;
import java.util.TreeSet;

public class 두_개_뽑아서_더하기 {

   public static void main(String[] args) {
      System.out.println(Arrays.toString(solution(new int[] {2, 1, 3, 4, 1})));
      System.out.println(Arrays.toString(solution(new int[] {5, 0, 2, 7})));
   }

   public static int[] solution(int[] numbers) {
      Set<Integer> set = new TreeSet<>();
      for (int i = 0; i < numbers.length; i++) {
         for (int j = 0; j < numbers.length; j++) {
            if (i == j)
               continue;
            set.add(numbers[i] + numbers[j]);
         }
      }

      int[] answer = new int[set.size()];
      Iterator<Integer> iterator = set.iterator();
      for (int i = 0; i < set.size(); i++) {
         answer[i] = iterator.next();
      }
      return answer;
   }

}