출제 링크 : programmers.co.kr/learn/courses/30/lessons/68644
import java.util.*;
class Solution {
public int[] solution(int[] numbers) {
TreeSet<Integer> answer = new TreeSet<Integer>();
for (int i = 0; i < numbers.length; i++) {
for (int j = i; j < numbers.length; j++) {
if (i == j)
continue;
answer.add(numbers[i] + numbers[j]);
}
}
return answer.stream().mapToInt(i -> i.intValue()).toArray();
}
}