SWEA 1986. 지그재그 숫자

SW Expert Academy

import java.util.*;


public class Solution {
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        int T = sc.nextInt();

        for (int i = 1; i <= T; i++) {
            int N = sc.nextInt();
            int sum = 0;
            for (int j = 1; j <= N; j++) {
                if(j%2 == 0){
                    sum -=j;
                } else if (j%2==1) {
                    sum +=j;
                }
            }
            System.out.printf("#%d %d\n", i, sum);
        }

    }
}