题解 | 记负均正

import java.util.Scanner;
import java.text.DecimalFormat;
// 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);
      while (sc.hasNextInt()) {
          int a = sc.nextInt();
          int [] arr = new int [a];
          int t=0;
          int z=0;
          double c=0;
          for (int i = 0; i < a; i++) {
              arr[i] = sc.nextInt();
              if (arr[i]< 0) {
                  t++;
              } else if (arr[i]==0) {
                  z++;
              } else {
                  c+=arr[i];
              }
          }
          double av=0;
          if (a-t-z==0) {
              av=0.0;
          }else {
               av=c/(a-t-z);
          } 
         
         // System.out.println(av);
          DecimalFormat df = new DecimalFormat("0.0");
          String str=df.format(av);
          System.out.println(t+" "+str);
      }
      sc.close();
    }
}