题解 | #记负均正#

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 in = new Scanner(System.in);
        int n = in.nextInt();
        int sum = 0;
        int neNum = 0;
        float poNum = 0;
        for (int i = 0; i < n; i++) {
            int num = in.nextInt();
            if (num > 0) {
                sum += num;
                poNum++;
            } else if (num < 0) {
                neNum++;
            }
        }
        System.out.format("%d %.1f", neNum, poNum == 0 ? poNum : sum / poNum);
    }
}