题目通过率&难度

用Map存储“题目-通过率”映射，用Collections.sort()排序键值，挨着打印即可：

import java.util.*;
public class Main{
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        Map<String, Double> m = new HashMap<>();
        int n = Integer.parseInt(sc.nextLine());
        for(int i = 0; i < n; ++i){
            String[] v = sc.nextLine().split(" ");
            m.put(v[0], (double)Integer.parseInt(v[2])/(double)Integer.parseInt(v[1]));
        }
        List<String> r = new ArrayList<>(m.keySet());
        Collections.sort(r);
        for(String s : r){
            System.out.print(s);
            System.out.print(" ");
            System.out.println(f(m.get(s)));
        }
    }
    static int f(double x){
        if(x <= 0.3) return 5;
        if(x > 0.6) return 3;
        return 4;
    }
}