Data commit

Task/Abelian-sandpile-model/Java/abelian-sandpile-model.java

@@ -0,0 +1,113 @@
+import java.awt.*;
+import java.awt.event.*;
+import javax.swing.*;
+
+public class AbelianSandpile {
+    public static void main(String[] args) {
+        SwingUtilities.invokeLater(new Runnable() {
+            public void run() {
+                Frame frame = new Frame();
+                frame.setVisible(true);
+            }
+        });
+    }
+
+    private static class Frame extends JFrame {
+        private Frame() {
+            super("Abelian Sandpile Model");
+            setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+            Container contentPane = getContentPane();
+            JPanel controlPanel = new JPanel(new FlowLayout(FlowLayout.LEFT));
+            JButton start = new JButton("Restart Simulation");
+            start.addActionListener(e -> restartSimulation());
+            JButton stop = new JButton("Stop Simulation");
+            stop.addActionListener(e -> stopSimulation());
+            controlPanel.add(start);
+            controlPanel.add(stop);
+            contentPane.add(controlPanel, BorderLayout.NORTH);
+            contentPane.add(canvas = new Canvas(), BorderLayout.CENTER);
+            timer = new Timer(100, e -> canvas.runAndDraw());
+            timer.start();
+            pack();
+        }
+
+        private void restartSimulation() {
+            timer.stop();
+            canvas.initGrid();
+            timer.start();
+        }
+
+        private void stopSimulation() {
+            timer.stop();
+        }
+
+        private Timer timer;
+        private Canvas canvas;
+    }
+
+    private static class Canvas extends JComponent {
+        private Canvas() {
+            setBorder(BorderFactory.createEtchedBorder());
+            setPreferredSize(new Dimension(600, 600));
+        }
+
+        public void paintComponent(Graphics g) {
+            int width = getWidth();
+            int height = getHeight();
+            g.setColor(Color.WHITE);
+            g.fillRect(0, 0, width, height);
+            int cellWidth = width/GRID_LENGTH;
+            int cellHeight = height/GRID_LENGTH;
+            for (int i = 0; i < GRID_LENGTH; ++i) {
+                for (int j = 0; j < GRID_LENGTH; ++j) {
+                    if (grid[i][j] > 0) {
+                        g.setColor(COLORS[grid[i][j]]);
+                        g.fillRect(i * cellWidth, j * cellHeight, cellWidth, cellHeight);
+                    }
+                }
+            }
+        }
+
+        private void initGrid() {
+            for (int i = 0; i < GRID_LENGTH; ++i) {
+                for (int j = 0; j < GRID_LENGTH; ++j) {
+                    grid[i][j] = 0;
+                }
+            }
+        }
+
+        private void runAndDraw() {
+            for (int i = 0; i < 100; ++i)
+                addSand(GRID_LENGTH/2, GRID_LENGTH/2);
+            repaint();
+        }
+
+        private void addSand(int i, int j) {
+            int grains = grid[i][j];
+            if (grains < 3) {
+                grid[i][j]++;
+            }
+            else {
+                grid[i][j] = grains - 3;
+                if (i > 0)
+                    addSand(i - 1, j);
+                if (i < GRID_LENGTH - 1)
+                    addSand(i + 1, j);
+                if (j > 0)
+                    addSand(i, j - 1);
+                if (j < GRID_LENGTH - 1)
+                    addSand(i, j + 1);
+            }
+        }
+
+        private int[][] grid = new int[GRID_LENGTH][GRID_LENGTH];
+    }
+
+    private static final Color[] COLORS = {
+        Color.WHITE,
+        new Color(0x00, 0xbf, 0xff),
+        new Color(0xff, 0xd7, 0x00),
+        new Color(0xb0, 0x30, 0x60)
+    };
+    private static final int GRID_LENGTH = 300;
+}