import java.awt.*;
 
public class AlgoVisualizer {
 
    private static int DELAY = 100;
 
    private SelectionSortData data;
    private AlgoFrame frame;
 
    public AlgoVisualizer(int sceneWidth, int sceneHeight, int N){
 
        data = new SelectionSortData(N, sceneHeight);
 
        // 初始化視圖
        EventQueue.invokeLater(() -> {
            frame = new AlgoFrame("Selection Sort Visualization", sceneWidth, sceneHeight);
            new Thread(() -> {
                run();
            }).start();
        });
    }
 
    private void run(){
        setData(0, -1, -1);
 
        for( int i = 0 ; i < data.N() ; i ++ ){
            // 尋找[i, n)區(qū)間里的最小值的索引
            int minIndex = i;
            setData(i, -1, minIndex);
            for( int j = i + 1 ; j < data.N() ; j ++ ){
                setData(i, j, minIndex);
                if( data.get(j) < data.get(minIndex) ){
                    minIndex = j;
                    setData(i, j, minIndex);
                }
            }
 
            data.swap(i , minIndex);
            setData(i +1 , -1, -1);
        }
        setData(data.N(), -1, -1);
    }
 
    private void setData(int orderedIndex, int currentCompareIndex, int currentMinIndex)
    {
        data.orderedIndex = orderedIndex;
        data.currentCompareIndex = currentCompareIndex;
        data.currentMinIndex = currentMinIndex;
 
        frame.render(data);
        AlgoVisHelper.pause(DELAY);
    }
 
    public static void main(String[] args) {
 
        int sceneWidth = 800;
        int sceneHeight = 800;
        int N = 100;
 
        AlgoVisualizer vis = new AlgoVisualizer(sceneWidth, sceneHeight, N);
    }
}

import java.awt.*;
import java.awt.geom.Ellipse2D;
 
import java.awt.geom.Rectangle2D;
import java.lang.InterruptedException;
 
public class AlgoVisHelper {
 
    private AlgoVisHelper(){}
 
    public static final Color Red = new Color(0xF44336);
    public static final Color Pink = new Color(0xE91E63);
    public static final Color Purple = new Color(0x9C27B0);
    public static final Color DeepPurple = new Color(0x673AB7);
    public static final Color Indigo = new Color(0x3F51B5);
    public static final Color Blue = new Color(0x2196F3);
    public static final Color LightBlue = new Color(0x03A9F4);
    public static final Color Cyan = new Color(0x00BCD4);
    public static final Color Teal = new Color(0x009688);
    public static final Color Green = new Color(0x4CAF50);
    public static final Color LightGreen = new Color(0x8BC34A);
    public static final Color Lime = new Color(0xCDDC39);
    public static final Color Yellow = new Color(0xFFEB3B);
    public static final Color Amber = new Color(0xFFC107);
    public static final Color Orange = new Color(0xFF9800);
    public static final Color DeepOrange = new Color(0xFF5722);
    public static final Color Brown = new Color(0x795548);
    public static final Color Grey = new Color(0x9E9E9E);
    public static final Color BlueGrey = new Color(0x607D8B);
    public static final Color Black = new Color(0x000000);
    public static final Color White = new Color(0xFFFFFF);
 
    public static void strokeCircle(Graphics2D g, int x, int y, int r){
 
        Ellipse2D circle = new Ellipse2D.Double(x-r, y-r, 2*r, 2*r);
        g.draw(circle);
    }
 
    public static void fillCircle(Graphics2D g, int x, int y, int r){
 
        Ellipse2D circle = new Ellipse2D.Double(x-r, y-r, 2*r, 2*r);
        g.fill(circle);
    }
 
    public static void strokeRectangle(Graphics2D g, int x, int y, int w, int h){
 
        Rectangle2D rectangle = new Rectangle2D.Double(x, y, w, h);
        g.draw(rectangle);
    }
 
    public static void fillRectangle(Graphics2D g, int x, int y, int w, int h){
 
        Rectangle2D rectangle = new Rectangle2D.Double(x, y, w, h);
        g.fill(rectangle);
    }
 
    public static void setColor(Graphics2D g, Color color){
        g.setColor(color);
    }
 
    public static void setStrokeWidth(Graphics2D g, int w){
        int strokeWidth = w;
        g.setStroke(new BasicStroke(strokeWidth, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND));
    }
 
    public static void pause(int t) {
        try {
            Thread.sleep(t);
        }
        catch (InterruptedException e) {
            System.out.println("Error sleeping");
        }
    }
 
}

import java.awt.*;
import javax.swing.*;
 
public class AlgoFrame extends JFrame{
 
    private int canvasWidth;
    private int canvasHeight;
 
    public AlgoFrame(String title, int canvasWidth, int canvasHeight){
 
        super(title);
 
        this.canvasWidth = canvasWidth;
        this.canvasHeight = canvasHeight;
 
        AlgoCanvas canvas = new AlgoCanvas();
        setContentPane(canvas);
        pack();
 
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setResizable(false);
 
        setVisible(true);
    }
 
    public AlgoFrame(String title){
 
        this(title, 1024, 768);
    }
 
    public int getCanvasWidth(){return canvasWidth;}
    public int getCanvasHeight(){return canvasHeight;}
 
    // data
    private SelectionSortData data;
    public void render(SelectionSortData data){
        this.data = data;
        repaint();
    }
 
    private class AlgoCanvas extends JPanel{
 
        public AlgoCanvas(){
            // 雙緩存
            super(true);
        }
 
        @Override
        public void paintComponent(Graphics g) {
            super.paintComponent(g);
 
            Graphics2D g2d = (Graphics2D)g;
 
            // 抗鋸齒
            RenderingHints hints = new RenderingHints(
                    RenderingHints.KEY_ANTIALIASING,
                    RenderingHints.VALUE_ANTIALIAS_ON);
            hints.put(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
            g2d.addRenderingHints(hints);
 
            // 具體繪制
            int w = canvasWidth/data.N();
 
            for(int i = 0 ; i < data.N() ; i ++ ) {
                if( i < data.orderedIndex)
                    AlgoVisHelper.setColor(g2d, AlgoVisHelper.Red);
                else
                    AlgoVisHelper.setColor(g2d, AlgoVisHelper.Grey);
 
                if( i == data.currentCompareIndex)
                    AlgoVisHelper.setColor(g2d, AlgoVisHelper.Indigo);
                if(i == data.currentMinIndex)
                    AlgoVisHelper.setColor(g2d, AlgoVisHelper.Green);
 
                AlgoVisHelper.fillRectangle(g2d, i * w, canvasHeight - data.get(i), w - 1, data.get(i));
            }
        }
 
        @Override
        public Dimension getPreferredSize(){
            return new Dimension(canvasWidth, canvasHeight);
        }
    }
}

public class SelectionSortData {
 
    private int[] numbers;
    public int orderedIndex = -1; //[0,....,orderedIndex)是有序的
    public  int currentMinIndex = -1; //當前找到的最小元素索引
    public  int currentCompareIndex = -1; //當前正在比較的元素索引
 
    public SelectionSortData(int N, int randomBound){
 
        numbers = new int[N];
 
//        數(shù)據(jù)不能為0
        for( int i = 0 ; i < N ; i ++)
            numbers[i] = (int)(Math.random()*randomBound) + 1;
    }
 
    public int N(){
        return numbers.length;
    }
 
    public int get(int index){
        if( index < 0 || index >= numbers.length)
            throw new IllegalArgumentException("Invalid index to access Sort Data.");
 
        return numbers[index];
    }
 
    public void swap(int i, int j) {
 
        if( i < 0 || i >= numbers.length || j < 0 || j >= numbers.length)
            throw new IllegalArgumentException("Invalid index to access Sort Data.");
 
        int t = numbers[i];
        numbers[i] = numbers[j];
        numbers[j] = t;
    }
}