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程序员用代码告诉你，千万别出门！

养码场 · 公众号 · · 2020-02-08 16:32

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前些天，一个视频火了起来。

事情是这样的，B 站 UP 主 @ele实验室，用了一夜的时间，写了一个简单的疫情传播仿真程序，告诉大家在家待着的重要性，视频如下：

点击查看视频

来自B站up主“Ele实验室”，版权属于原作者

现在，作者已经将代码开源到 GitHub 上，场主特此 download 下来分享给大家。
GitHub 地址如下：
https://github.com/KikiLetGo/VirusBroadcast

此后，有人解析了VirusBroadcast的程序代码，下面我们就来看看它是如何一步步实现的吧!

这个程序主要利用“高斯分布”算法，简单的模拟病毒传播的场景。它由以下程序片段构成

1、病毒对象

2、床位【隔离对象】

3、主要参数【初始状态】，假设没有隔离，潜伏期为一天

public class Constants {    public static int ORIGINAL_COUNT=50;//初始感染数量    public static float BROAD_RATE = 0.8f;//传播率    public static float SHADOW_TIME = 1;//潜伏时间    public static int HOSPITAL_RECEIVE_TIME=10;//医院收治响应时间    public static int BED_COUNT=0;//医院床位    public static float u=0.99f;//流动意向平均值}

4、医院对象，随机分布，产生床位

public class Hospital {    private int x=800;    private int y=110;
    private int width;    private int height=606;    public int getWidth() {        return width;    }    public int getHeight() {        return height;    }
    public int getX() {        return x;    }
    public int getY() {        return y;    }
    private static Hospital hospital = new Hospital();    public static Hospital getInstance(){        return hospital;    }    private Point point = new Point(800,100);    private List beds = new ArrayList<>();
    private Hospital() {        if(Constants.BED_COUNT==0){            width=0;            height=0;        }        int column = Constants.BED_COUNT/100;        width = column*6;        for(int i=0;i            for(int j=10;j<=610;j+=6){                Bed bed = new Bed(point.getX()+i*6,point.getY()+j);                beds.add(bed);            }        }    }
    public Bed pickBed(){        for(Bed bed:beds){            if(bed.isEmpty()){                return bed;            }        }        return null;    }

5、流动目的性

public class MoveTarget {    private int x;    private int y;    private boolean arrived=false;
    public MoveTarget(int x, int y) {        this.x = x;        this.y = y;    }
    public int getX() {        return x;    }
    public void setX(int x) {        this.x = x;    }
    public int getY() {        return y;    }
    public void setY(int y) {        this.y = y;    }
    public boolean isArrived() {        return arrived;    }
    public void setArrived(boolean arrived) {        this.arrived = arrived;    }}

6、人员【流动及感染】

public




    
 class Person {    private City city;    private int x;    private int y;    private MoveTarget moveTarget;    int sig=1;    double targetXU;    double targetYU;    double targetSig=50;    public interface State{        int NORMAL = 0;        int SUSPECTED = NORMAL+1;        int SHADOW = SUSPECTED+1;        int CONFIRMED = SHADOW+1;        int FREEZE = CONFIRMED+1;        int CURED = FREEZE+1;    }
    public Person(City city, int x, int y) {        this.city = city;        this.x = x;        this.y = y;        targetXU = 100*new Random().nextGaussian()+x;        targetYU = 100*new Random().nextGaussian()+y;
    }    public boolean wantMove(){        double value = sig*new Random().nextGaussian()+Constants.u;        return value>0;    }
    private int state=State.NORMAL;
    public int getState() {        return state;    }
    public void setState(int state) {        this.state = state;    }
    public int getX() {        return x;    }
    public void setX(int x) {        this.x = x;    }
    public int getY() {        return y;    }
    public void setY(int y) {        this.y = y;    }    int infectedTime=0;    int confirmedTime=0;    public boolean isInfected(){        return state>=State.SHADOW;    }    public void beInfected(){        state = State.SHADOW;        infectedTime=MyPanel.worldTime;    }
    public double distance(Person person){        return Math.sqrt(Math.pow(x-person.getX(),2)+Math.pow(y-person.getY(),2));    }
    private void freezy(){        state = State.FREEZE;    }    private void moveTo(int x,int y){        this.x+=x;        this.y+=y;    }    private void action(){        if(state==State.FREEZE){            return;        }        if(!wantMove()){            return;        }        if(moveTarget==null||moveTarget.isArrived()){
            double targetX = targetSig*new Random().nextGaussian()+targetXU;            double targetY = targetSig*new Random().nextGaussian()+targetYU;            moveTarget = new MoveTarget((int)targetX,(int)targetY);
        }





    

        int dX = moveTarget.getX()-x;        int dY = moveTarget.getY()-y;        double length=Math.sqrt(Math.pow(dX,2)+Math.pow(dY,2));
        if(length<1){            moveTarget.setArrived(true);            return;        }        int udX = (int) (dX/length);        if(udX==0&&dX!=0){            if(dX>0){                udX=1;            }else{                udX=-1;            }        }        int udY = (int) (dY/length);        if(udY==0&&udY!=0){            if(dY>0){                udY=1;            }else{                udY=-1;            }        }
        if(x>700){            moveTarget=null;            if(udX>0){                udX=-udX;            }        }        moveTo(udX,udY);

    }
    private float SAFE_DIST = 2f;
    public void update(){        if(state>=State.FREEZE){            return;        }        if(state==State.CONFIRMED&&MyPanel.worldTime-confirmedTime>=Constants.HOSPITAL_RECEIVE_TIME){            Bed bed = Hospital.getInstance().pickBed();            if(bed==null){                System.out.println("隔离区没有空床位");            }else{                state=State.FREEZE;                x=bed.getX();                y=bed.getY();                bed.setEmpty(false);            }        }        if(MyPanel.worldTime-infectedTime>Constants.SHADOW_TIME&&state==State.SHADOW){            state=State.CONFIRMED;            confirmedTime = MyPanel.worldTime;        }
        action();
        List people = PersonPool.getInstance().personList;        if(state>=State.SHADOW){            return;        }       for(Person person:people){           if(person.getState()== State.NORMAL){               continue;           }           float random = new Random().nextFloat();           if(random               this.beInfected();           }       }    }}

7、汇总人数

public class PersonPool {    private static PersonPool personPool = new PersonPool();    public static PersonPool getInstance(){        return personPool;    }
    List personList = new ArrayList();
    public List getPersonList() {        return personList;    }
    private PersonPool() {        City city = new City(400,400);        for (int i = 0; i < 5000




    
; i++) {            Random random = new Random();            int x = (int) (100 * random.nextGaussian() + city.getCenterX());            int y = (int) (100 * random.nextGaussian() + city.getCenterY());            if(x>700){                x=700;            }            Person person = new Person(city,x,y);            personList.add(person);        }    }}

8、分布点

9、显示面板，设置色块【红色：感染黄色：潜伏绿色：安全】

public class MyPanel extends JPanel implements Runnable {   private int pIndex=0;    public MyPanel() {        this.setBackground(new Color(0x444444));    }
    @Override    public void paint(Graphics arg0) {        super.paint(arg0);        //draw border        arg0.setColor(new Color(0x00ff00));        arg0.drawRect(Hospital.getInstance().getX(),Hospital.getInstance().getY(),                Hospital.getInstance().getWidth(),Hospital.getInstance().getHeight());        List people = PersonPool.getInstance().getPersonList();        if(people==null){            return;        }        people.get(pIndex).update();        for(Person person:people){
            switch (person.getState()){                case Person.State.NORMAL:{                    arg0.setColor(new Color(0xdddddd));
                }break;                case Person.State.SHADOW:{                    arg0.setColor(new Color(0xffee00));
                }break;                case Person.State.CONFIRMED:                case Person.State.FREEZE:{                    arg0.setColor(new Color(0xff0000));
                }break;            }            person.update();            arg0.fillOval(person.getX(), person.getY(), 3, 3);
        }        pIndex++;        if(pIndex>=people.size()){            pIndex=0;        }    }
    public static int worldTime=0;    @Override    public void run() {        while (true) {
            this.repaint();
            try {                Thread.sleep(100

程序员用代码告诉你，千万别出门！

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