package Undone;

import java.util.*;

class mydata implements Comparable<mydata>{

int x;

int y;

mydata(int x2,int y2){

this.x=x2;

this.y=y2;

}

@Override

public int compareTo(mydata o) {

// TODO Auto-generated method stub

if(this.x==o.x)

{

return this.y-o.y;

}

return this.x-o.x;

}

@Override

public String toString() {

return x+" "+y;

}

}

public class a915 {

//a915: 二维点排序

public static void main(String[] args) {

// TODO Auto-generated method stub

Scanner sc=new Scanner(System.in);

List<mydata> data=new ArrayList();

int num=sc.nextInt();

for(int i=0;i<num;i++)

{

int x=sc.nextInt();

int y=sc.nextInt();

data.add(new mydata(x,y));

}

Collections.sort(data);

for(int i=0;i<data.size();i++)

{

System.out.println(data.get(i));

}

}

}

把mydata這個類別寫在a915裡面就可以了