题解 | #牛牛学数列#
牛牛学数列
https://www.nowcoder.com/practice/0b97367cd2184c12a0e02f7c223aee11
import java.util.Scanner; // 注意类名必须为 Main, 不要有任何 package xxx 信息 public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); int n = sc.nextInt(); int sum = 0; for (int i = 1; i <= n; i++) { if (i % 2 != 0) { //如果是奇数 sum += i; } else { sum -= i; } } System.out.println(sum); } }