Java比较器（成绩排序）

题目链接

版本1

外置重载比较器类

import java.util.*;
public class perfomanceSort {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        while(in.hasNext()) {
            int n = in.nextInt();
            String s;
            int age, score;
            Student stu[]= new Student[n];
            for( int i = 0; i < n; i++) {
                s = in.next();
                age = in.nextInt();
                score = in.nextInt();
                stu[i] = new Student(s, age, score);
            }
            Arrays.sort(stu, new cmp());
            for(int i = 0; i < n; i++) {
                System.out.println(stu[i].name+" "+stu[i].age+" "+stu[i].score);
            }
        }
    }
    public static class Student{
        public int age;
        public int score;
        public String name;
        Student(String name, int age, int score){
            this.age = age;
            this.name = name;
            this.score = score;
        }
        }
    public static class cmp implements Comparator<Student>{  


        public int compare(Student s1, Student s2) {
            if(s1.score != s2.score) return s1.score < s2.score ? -1: 1; 
            else if(s1.name.compareTo(s2.name) != 0) return s1.name.compareTo(s2.name) < 0 ? -1: 1;
                return s1.age < s2.age ? -1: 1;
        }
    }

}

版本2

内置比较器

import java.util.Arrays;
import java.util.Comparator;
import java.util.Scanner;


public class second {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        while(in.hasNext()) {
            int n = in.nextInt();
            Student stu[] = new Student[n];
            for( int i = 0; i < n; i++) {
                stu[i]=new Student(in.next(), in.nextInt(), in.nextInt());
            }
             Arrays.sort(stu, new Comparator<Student>() {

                 public int compare(Student o1, Student o2) {
                     if(o1.score == o2.score){
                       if(o1.name.compareTo(o2.name) == 0){
                           return o1.age - o2.age;
                       }
                       return o1.name.compareTo(o2.name);
                     }
                     return o1.score - o2.score;
                 }
             });

            for(int i = 0; i < n; i++) {
                System.out.println(stu[i].name+" "+stu[i].age+" "+stu[i].score);
            }
        }
    }
    public static class Student{
        int age;
        int score;
        String name;
        Student(String name, int age, int score){
            this.age = age;
            this.name = name;
            this.score = score;
        }
    }


}

版本3

• 2021.04.03

• 主要考点：数组排序，重写Comparator方法

  import java.util.*;
  public class Main{
  
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        String name;
        int age, score;
        List<Stu> list = new ArrayList();
        for(int i = 0; i < n; i++){
                name = in.next();
                age = in.nextInt();
                score = in.nextInt();
                list.add(new Stu(name, age,score));
        }
        // 排序
        Collections.sort(list, (o1, o2) -> {
            if(o1.score != o2.score) return o1.score - o2.score;
            else if(!o1.name.equals(o2.name)) return o1.name.compareTo(o2.name);
            else return o1.age - o2.age;
        });
  
        // 输出
        for(Stu s: list){
            System.out.println(s.name+" "+s.age +" "+s.score);
        }
    }
    public static class Stu{
        String name;
        int age;
        int score;
  
        public Stu(String name, int age, int score) {
            this.name = name;
            this.age = age;
            this.score = score;
        }
    }
  }