import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class Bernoulli extends JFrame {

	public static void main(String[] args) {
		new Bernoulli("Bernoulli");
	}

	public Bernoulli(String title) {
		super(title);

		this.setSize(1000, 680);

		JPanel panel = new BernoulliPanel();
		Container content = this.getContentPane();

		content.add(panel, BorderLayout.CENTER);

		this.setDefaultCloseOperation(EXIT_ON_CLOSE);
		this.setVisible(true);
	}

	public class BernoulliPanel extends JPanel {

		Font font = new Font("Georgia", Font.PLAIN, 14);

		@Override
		public void paintComponent(Graphics g) {
			int w = this.getSize().width;
			int h = this.getSize().height;

			g.setColor(Color.white);
			g.fillRect(0, 0, w, h);

			g.setColor(Color.black);
			g.setFont(font);

			this.drawBernoulli(15, g, 10, 10, 60, 40);

		}

		void drawRational(Rational r, Graphics g, int x, int y, int w, int h) {
			FontMetrics metrics = g.getFontMetrics(font);
			int hgt = metrics.getHeight();
			int pady = (h - hgt) / 2 + hgt;

			if (r.p != 0 && r.q != 1) {
				{
					String text = String.valueOf(r.p);
					int adv = metrics.stringWidth(text);
					int padx = (w - adv) / 2;

					g.drawString(text, x + padx, y + pady - hgt / 2);
				}
				{
					String text = String.valueOf("------");
					int adv = metrics.stringWidth(text);
					int padx = (w - adv) / 2;

					g.drawLine(x + padx, y + pady - hgt * 1 / 3, w - padx + x,
							y + pady - hgt * 1 / 3);
				}
				{
					String text = String.valueOf(r.q);
					int adv = metrics.stringWidth(text);
					int padx = (w - adv) / 2;

					g.drawString(text, x + padx, y + pady + hgt / 2);
				}
			} else {
				{
					String text = String.valueOf(r.p);
					int adv = metrics.stringWidth(text);
					int padx = (w - adv) / 2;
					g.drawString(text, x + padx, y + pady);
				}
			}
		}

		void drawBernoulli(int kmax, Graphics g, int x, int y, int w, int h) {

			Rational[] p = new Rational[kmax];

			for (int k = 0; k < kmax; k++) {

				for (int m = 0; m < kmax - k; m++) {

					if (k == 0) {
						p[m] = new Rational(1, m + 1);

					} else {
						p[m] = p[m].sub(p[m + 1]).mul(new Rational(m + 1, 1));

					}

					if (m == 0) {
						Color c = g.getColor();
						g.setColor(new Color(255, 128, 128));
						g.fillRect(x + w * m, y + h * k, w, h);
						g.setColor(c);
						g.drawRect(x + w * m, y + h * k, w, h);
						this.drawRational(p[m], g, x + w * m, y + h * k, w, h);
						g.setColor(c);
					} else {
						g.drawRect(x + w * m, y + h * k, w, h);
						this.drawRational(p[m], g, x + w * m, y + h * k, w, h);
					}

				}
			}
		}

		public class Rational {

			long p;
			long q;

			public Rational(long p, long q) {
				this.p = p;
				this.q = q;
			}

			public Rational sub(Rational v) {
				Rational n = new Rational(p, q);

				n.p = this.p * v.q - this.q * v.p;
				n.q = this.q * v.q;

				return n.reduction();
			}

			public Rational mul(Rational v) {
				Rational n = new Rational(p, q);

				n.p = this.p * v.p;
				n.q = this.q * v.q;

				return n.reduction();
			}

			public String toString() {
				if (p != 0 && q != 1)
					return "[" + p + "/" + q + "]";
				else
					return "[" + p + "]";
			}

			private long abs(long a) {
				return a >= 0 ? a : -a;
			}

			private Rational reduction() {
				long flag = p * q >= 0 ? 1 : -1;
				long[] a = { abs(p), abs(q) };

				if (a[0] == 0) {
					q = 1;
					return this;
				}
				if (a[0] == a[1]) {
					p = 1 * flag;
					q = 1;
					return this;
				}

				if (a[0] < a[1]) {
					swap(a);
				}

				long r;
				while ((r = a[0] % a[1]) != 0) {
					a[0] = a[1];
					a[1] = r;
				}

				p = abs(p) * flag / a[1];
				q = abs(q) / a[1];

				return this;

			}

			private void swap(long[] a) {
				long temp = a[0];
				a[0] = a[1];
				a[1] = temp;
			}
		}

	}

}