平安科技笔试题：学生平均分排序

有没有老哥A掉这道题，，，可能我是真的菜，下面是我的代码用的java原生的排序，重写了Comparator的compareTo方法，不懂为什么只A了50% ——————想知道剩下的50%是什么情况orz~

import java.util.*;
public class Main {
    private static Scanner sc = new Scanner(System.in);
    public static void main(String[] args) {
        ArrayList<Stu> list = new ArrayList<>();
        while (sc.hasNextLine()) {
            String[] str = sc.nextLine().trim().split(" ");
            String name = str[0];
            int count = 0;
            int sum = 0;
            for (int i = 1; i < str.length; ++i) {
                sum += Integer.valueOf(str[i]);
                count += 1;
            }
            int avg = sum / count;
            list.add(new Stu(name, avg));
        }
        list.sort(Comparator.comparingInt(Stu::getAvg));
        for (Stu s : list) {
            System.out.println(s);
        }
    }
}
class Stu {
    private String name;
    private int avg;
    Stu(String name, int avg) {
        this.name = name;
        this.avg = avg;
    }
    public int getAvg() {
        return avg;
    } @Override public String toString() {
        return name + " " + avg;
    }
}