题解 | #记负均正#

import java.util.*;
public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int n = Integer.valueOf(scan.nextLine().trim());
        String[] numsStr = scan.nextLine().split(" ");
        int negativeNums = 0;
        int positiveNums = 0;
        int positiveTotal = 0;
        for (String numStr : numsStr) {
            int num = Integer.valueOf(numStr);
            if (num < 0) {
                negativeNums++;
            } else if (num > 0) {
                positiveNums++;
                positiveTotal += num;
            }
        }
        System.out.printf("%d %.1f", negativeNums, positiveNums == 0 ? 0.0 : (double) positiveTotal / positiveNums);
    }
}