成绩排序

import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;
import java.util.TreeMap;

// 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 scanner = new Scanner(System.in);
		while(scanner.hasNext()) {
			int n = scanner.nextInt();
			Map<Integer, Integer> myMap = new TreeMap<Integer, Integer>();
			for (int i = 0; i < n; i++) {
				int sno = scanner.nextInt();
				int sgrade = scanner.nextInt();
				myMap.put(sno, sgrade);
			}
			
			//使用list对entrySet排序
			List<Map.Entry<Integer, Integer>> myList = new ArrayList<>(myMap.entrySet());
			myList.sort(Map.Entry.comparingByValue());
			
			//创建一个LinkedHashMap,按照排序后的顺序插入entry
			Map<Integer, Integer> sortedMap = new LinkedHashMap<Integer, Integer>();
			for(Map.Entry<Integer, Integer> entry : myList) {
				sortedMap.put(entry.getKey(), entry.getValue());
			}
			
			
			for(Map.Entry<Integer, Integer> entry:sortedMap.entrySet()) {
				System.out.println(entry.getKey()+" "+entry.getValue());
			}

		}
	}
}

import java.util.*;

public class Main{
    
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        while(in.hasNext()){
            int n = Integer.parseInt(in.nextLine());
            String[] inputs = new String[n];
            for(int i=0;i<n;i++){
                String[] item = in.nextLine().split(" ");
                if(Integer.parseInt(item[0])<10){
                    //因为n<=100,补零为了后面排序
                    item[0] = "0"+item[0];
                }
                inputs[i] = item[1]+" "+item[0];
            }
            //排序
            Arrays.sort(inputs);
            for(int i=0;i<n;i++){
               String[] item = inputs[i].split(" ");
               if(Integer.parseInt(item[1])<10){
                   //去掉前面补的零
                   item[1] = item[1].substring(1,2);
               }
               String temp = item[1]+" "+item[0];
               System.out.println(temp);
            }
            
        }
    
    }
}

public class Main {
    public static void main(String[]args){
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        Student[] students = new Student[n];
        for(int i=0;i<n;i++){
            int number = scanner.nextInt();
            int grade = scanner.nextInt();
            students[i] = new Student(grade, number);
        }
        Arrays.stream(students)
                .sorted((o1, o2) -> o1.grade == o2.grade ? o1.number - o2.number : o1.grade - o2.grade)
                .forEach(System.out::println);
    }
}
class Student{
    int grade;
    int number;
    public Student(int grade, int number) {
        this.grade = grade;
        this.number = number;
    }
    @Override
    public String toString() {
        return number + " " + grade;
    }
}

Student类中几个set方法never used，可删掉，写的时候都写了，习惯。

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

class Student {
    private int id;
    private int grade;

    public Student(int id, int grade) {
        this.id = id;
        this.grade = grade;
    }

    public void setId(int id) {
        this.id = id;
    }

    public int getId() {
        return id;
    }

    public void setGrade(int grade) {
        this.grade = grade;
    }

    public int getGrade() {
        return grade;
    }

    public String toString() {
        return id + " " + grade;
    }
}

public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        while (scan.hasNext()) {
            int n = scan.nextInt();
            Student[] arr = new Student[n];
            for (int i = 0; i < arr.length; i++) {
                int id = scan.nextInt();
                int grade = scan.nextInt();
                arr[i] = new Student(id, grade);
            }
            Arrays.sort(arr, new MyComparator());
            for (int i = 0; i < arr.length; i++) {
                System.out.println(arr[i].toString());
            }
        }
    }

    private static class MyComparator implements Comparator {
        @Override
        public int compare(Object o1, Object o2) {
            Student s1 = (Student) o1;
            Student s2 = (Student) o2;
            if (s1.getGrade() != s2.getGrade()) {
                return s1.getGrade() > s2.getGrade() ? 1 : -1;
            } else {
                return s1.getId() > s2.getId() ? 1 : -1;
            }
        }
    }
}

import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;

/**
 * Created by fhqplzj on 17-1-26 at 下午1:08.
 */
public class My4 {
    static class Student implements Comparable<Student> {
        private int index;
        private int score;

        Student(int index, int score) {
            this.index = index;
            this.score = score;
        }

        @Override
        public String toString() {
            return String.format("%d %d", index, score);
        }

        @Override
        public int compareTo(Student o) {
            if (score != o.score) {
                return score < o.score ? -1 : 1;
            } else {
                return new Integer(index).compareTo(o.index);
            }
        }
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        ArrayList<Student> students = new ArrayList<>();
        while (scanner.hasNextInt()) {
            int n = scanner.nextInt();
            for (int i = 0; i < n; i++) {
                students.add(new Student(scanner.nextInt(), scanner.nextInt()));
            }
            Collections.sort(students);
            for (Student student : students) {
                System.out.println(student);
            }
        }
    }
}