import java.awt.*;
import java.awt.event.*;

import javax.swing.*;

public class Exercise6_37 extends JApplet implements ActionListener {
	int totalNumberOfDisks;
	int numberOfDisksToMove;

	int singularityPillar = 1;
	int doomPillar = 3;

	int tempPillar = 2;

	int stepsCounter = 0;

	JLabel inputLabel;
	JTextField inputField;

	JTextArea outputArea;
	JScrollPane scroller;

	public void init() {
		Container container = getContentPane();
		container.setLayout(new FlowLayout());

		inputLabel = new JLabel("輸入盤子的總數：");
		container.add(inputLabel);

		inputField = new JTextField(15);
		inputField.addActionListener(this);
		container.add(inputField);

		outputArea = new JTextArea(18, 15);
		scroller = new JScrollPane(outputArea);
		container.add(scroller);

	}

	public void actionPerformed(ActionEvent actionEvent) {
		outputArea.setText("");
		stepsCounter = 0;
		totalNumberOfDisks = Integer.parseInt(inputField.getText());
		numberOfDisksToMove = totalNumberOfDisks;

		tower(numberOfDisksToMove, singularityPillar, doomPillar, tempPillar);

		outputArea.append("\n\n共需要 " + stepsCounter + "	步！");
	}

	public void tower(int numberOfDisksToMove, int pillarNoDisksAt,
			int pillarNoDisksMoveTo, int tempPillar_) {
		if (numberOfDisksToMove == 1) {
			outputArea.append("第 " + (++stepsCounter) + "	步：" + pillarNoDisksAt
					+ " -> " + pillarNoDisksMoveTo + "\n");
		} else {
			tower(numberOfDisksToMove - 1, pillarNoDisksAt, tempPillar_,
					pillarNoDisksMoveTo);

			tower(1, pillarNoDisksAt, pillarNoDisksMoveTo, tempPillar);

			tower(numberOfDisksToMove - 1, tempPillar_, pillarNoDisksMoveTo,
					pillarNoDisksAt);

		}
	}
}