成绩排序

题目：牛客网

解题思路：

输入有2个属性，分别是用户名和成绩

1、定义一个class Student ，包含两个属性，分别是name和score

2、定义一个list，其元素是Student类，按照输入的内容将用户添加到list中

3、使用Collections容器进行排序，因为要按照score属性进行排序，需要提供Comparator

 

package offer;

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

class Student{
	public String name;
	public int score;
	public Student(String name , int score){
		this.name = name;
		this.score = score;
	}
}

public class Main {
	public static void sortStudent(int flag, ArrayList<Student> stulist){
		//引入Comparator，指定比较的算法
		if(flag == 1){
			Comparator<Student> c = new Comparator<Student>() {
				@Override
				//compare函数返回值大于0则交换o1和o2，小于0则不交换
				public int compare(Student o1, Student o2) {
					// TODO Auto-generated method stub
					return o1.score-o2.score;
				}
	        };
	        Collections.sort(stulist, c); 
		}
		else{
			Comparator<Student> c = new Comparator<Student>() {
				@Override
				public int compare(Student o1, Student o2) {
					// TODO Auto-generated method stub
					return o2.score-o1.score;
				}
	        };
	        Collections.sort(stulist, c); 
		}
		for(int i = 0; i < stulist.size(); i++){
			System.out.printf("%s %d%n", stulist.get(i).name, stulist.get(i).score);
		}
	}
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner in = new Scanner(System.in);
		while(in.hasNext()){
			int num = in.nextInt();
			int flag = in.nextInt();
			ArrayList<Student> stulist = new ArrayList<Student>();
			for(int i = 0; i < num; i++){
				String stuName = in.next();
				int stuScore = in.nextInt();
				stulist.add(new Student(stuName , stuScore));
			}
			sortStudent(flag, stulist);
		    
		}

	}

}