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);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextInt()) { // 注意 while 处理多个 case
            int num = in.nextInt();
            int temp;
            int countNeg = 0;
            int sum = 0;
            int count = 0;
            for(int i = 0; i < num; i++){
                temp = in.nextInt();
                if(temp < 0){
                    countNeg++;
                }else if(temp > 0){
                    sum += temp;
                    count++;
                }
            }
            System.out.print(countNeg + " ");
            System.out.printf("%.1f", count > 0?(double)sum/count : 0);            
        }
    }
}