[프로그래머스/Java] 약수의 개수와 덧셈

-Code

import java.util.*;

class Solution {
    public int solution(int left, int right) {
        int answer = 0;
        for (int i = left; i <= right; i++) {
            answer += isOk(i) ? i : -i;
        }

        return answer;
    }

    public static boolean isOk(int n) {
        List<Integer> measures = new ArrayList<>();
        for (int i = 1; i <=  n / 2; i++) {
            if (n % i == 0) measures.add(i);
        }
        measures.add(n);
        return measures.size() % 2 == 0;
    }
}