SWEA 1986 지그재그 숫자 D2 (자바 Java)

import java.util.Scanner;
import java.io.FileInputStream;
 
class Solution
{
    public static void main(String args[]) throws Exception
    {
        Scanner sc = new Scanner(System.in);
        int T;
        T=sc.nextInt();
 
        for(int test_case = 1; test_case <= T; test_case++)
        {
            int n = sc.nextInt();
            int sum = 0;
 
            for (int i = 1; i <= n; i++) {
                if (i % 2 == 1) {
                    sum += i;
                } else {
                    sum -= i;
                }
            }
            System.out.println("#" + test_case + " " + sum);
        }
    }
}