题解 | #记负均正#

import java.util.ArrayList;
import java.util.Scanner;

public class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while (sc.hasNext()) {
            ArrayList<Integer> positive = new ArrayList<>();
            ArrayList<Integer> negative = new ArrayList<>();
            int number = Integer.parseInt(sc.nextLine().trim());
            String[] strArr = sc.nextLine().trim().split("\\s+");
            for (int i = 0; i <number; i++) {
                int num= Integer.parseInt(strArr[i].trim());
                if(num>0){
                    positive.add(num);
                }else if(num<0) {
                    negative.add(num);
                }
            }
            System.out.print(negative.size()+" ");
            System.out.println(String.format("%.1f",sum(positive)));
        }
    }

    private static double sum(ArrayList<Integer> positive) {
        double d =0;
        for (int i = 0; i < positive.size(); i++) {
            d+=positive.get(i);
        }
        return (double) d/positive.size();
    }
}