[SWEA][D2] 1986. 지그재그 숫자 Java

import java.util.Scanner;  
  
public class zigzag {  
    public static void main(String[] args) {  
  
        Scanner sc = new Scanner(System.in);  
        int T = sc.nextInt();  
        sc.nextLine();  
          
        for (int test_case = 1; test_case <= T; test_case++) {  
            int num = sc.nextInt();  
            int sum = 0;  
  
            for (int i = 1; i <= num ; i++) {  
                sum += i % 2 ==1 ? i : -i;  
            }  
            System.out.println("#"+test_case + " "+ sum);  
        }  
    }  
}