正文之前

毕业论文肝到14000实在是肝不动了，必须开点新模块才能走得动，不然没法搞。所以最近在琢磨离散化这个东西。主要是参考的这个文献

我在Youtube上偶然看的一个小姐姐，然后痴迷于她的舞蹈。。

正文

好吧，这个只是个Part，做个笔记而已，不必较真！

Java中ArrayList的去重复及排序

这个是我当时参考的，结果不能排序！！

先把他的代码八一八：

package com.lj.test;

public class Student implements Comparable<Student>{

    private String name;
    private int age;

    public Student() {
        super();
    }

    public Student(String studnet, int age) {
        super();
        this.name = studnet;
        this.age = age;
    }

    public String getStudnet() {
        return name;
    }

    public void setStudnet(String studnet) {
        this.name = studnet;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "Student [studnet=" + name + ", age=" + age + "]";
    }

    @Override
    public int compareTo(Student o) {
        int num = this.age - o.age;
        int num2 = num == 0 ?this.name.compareTo(o.name):num;
        return num2;
    }   
}

package com.lj.test;

public class Student implements Comparable<Student>{

    private String name;
    private int age;

    public Student() {
        super();
    }

    public Student(String studnet, int age) {
        super();
        this.name = studnet;
        this.age = age;
    }

    public String getStudnet() {
        return name;
    }

    public void setStudnet(String studnet) {
        this.name = studnet;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "Student [studnet=" + name + ", age=" + age + "]";
    }

    @Override
    public int compareTo(Student o) {
        int num = this.age - o.age;
        int num2 = num == 0 ?this.name.compareTo(o.name):num;
        return num2;
    }   
}

这是应用！！

package com.lj.test;

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

public class ArrayListDemo3 {
    public static void main(String[] args) {

        ArrayList<Student> arrayList = new ArrayList<Student>();

        Student s1 = new Student("pirlo",21);
        Student s3 = new Student("范厨师",23);
        Student s4 = new Student("马师傅",21);
        Student s5 = new Student("非洲德化",24);
        Student s6 = new Student("pirlo",22);

        arrayList.add(s1);
        arrayList.add(s3);
        arrayList.add(s4);
        arrayList.add(s5);
        arrayList.add(s6);

        Collections.sort(arrayList);
        for(Student s : arrayList){
            System.out.println(s);
        }
    }
}

结果，我跑起来根本没有那个效果，排序？不存在的！！

然后我还纳闷呢！！怎么回事呢？？

直到后来，又看了一个博客！
如何实现对ArrayList排序 sort() - CSDN博客

Comparator返回值在jdk1.7、jdk1.8里必须是一对相反数，如1和-1，不能是1和0.因为1.7的排序算法采用timsort，对返回值有严格要求这是重头戏！！然后我就可以了！！

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

class NewData  implements Comparable<NewData>{
    private float sensor;
    private float category;
    NewData(float a, float b){
        super();
        this.sensor = a;
        this.category = b;
    }
    @Override
    public String toString() {
        return "\n[Sensor:" + sensor + ", category=" + category + "]";
    }
    @Override
    public int compareTo(NewData o) {
        return this.sensor>o.sensor?1:-1;
    }
}
public class EADC{
    public static void main(String[] args) {
        float[][] dat = new float[15][6];
        Scanner in = new Scanner(System.in);
        for(int i=0; i<15;++i){
            for(int s=0;s<6;++s){
                dat[i][s] = in.nextFloat();
            }
        }
        ArrayList<Float> sensor = new ArrayList<>();
        ArrayList<NewData> LIST = new ArrayList<>();
        for(int i=0;i<15;++i){
            if(!sensor.contains(dat[i][1])){
                sensor.add(dat[i][1]);
                LIST.add(new NewData(dat[i][1], dat[i][5]));
                //便利旧集合没有就添加到新集合
            }
        }
        Collections.sort(LIST);
        System.out.println(LIST);
    }
}

结果，很美:

/Library/Java/JavaVirtualMachines/jdk-9.0.1.jdk/Contents/Home/bin/java "-javaagent:/Applications/IntelliJ IDEA.app/Contents/lib/idea_rt.jar=50679:/Applications/IntelliJ IDEA.app/Contents/bin" -Dfile.encoding=UTF-8 -classpath /Users/zhangzhaobo/IdeaProjects/Test_of_Java/out/production/Test_of_Java EADC
2.0 2.0 -2.0 -2.0 0.0 0.0 
-1.0 -4.0 3.0 0.0 0.0 0.0 
-0.0 -2.0 0.0 -6.0 0.0 0.0 
-0.0 0.0 -1.0 -1.0 0.0 0.0 
5.0 2.0 -4.0 2.0 0.0 0.0 
-1.0 5.0 -1.0 -3.0 0.0 0.0 
-4.0 1.0 -0.0 -2.0 0.0 0.0 
-6.0 8.0 2.0 -1.0 0.0 0.0 
1.0 -0.0 -0.0 -0.0 0.0 0.0 
-3.0 -2.0 0.0 2.0 0.0 0.0 
2.0 -1.0 1.0 0.0 0.0 0.0 
4.0 -1.0 -2.0 -0.0 0.0 0.0 
-4.0 2.0 -1.0 -0.0 0.0 0.0 
0.0 10.0 -1.0 -4.0 0.0 0.0 
2.0 7.0 2.0 -0.0 0.0 0.0 [
[Sensor:-4.0, category=0.0], 
[Sensor:-2.0, category=0.0], 
[Sensor:-1.0, category=0.0], 
[Sensor:-0.0, category=0.0], 
[Sensor:0.0, category=0.0], 
[Sensor:1.0, category=0.0], 
[Sensor:2.0, category=0.0], 
[Sensor:5.0, category=0.0], 
[Sensor:7.0, category=0.0], 
[Sensor:8.0, category=0.0], 
[Sensor:10.0, category=0.0]]


Process finished with exit code 0

完美运行，所以说自定义的sort要返回值是-1 和 1！不能是1，0

正文之后

溜了，继续肝！！！明天还有音控员的笔试。。日了狗了！