1 2018.11.7
  2 XT
  3 
  4 /**
  5  * 功能：構造二叉樹
  6  * 說明：
  7  * 1.主函數輸入模式有兩種，BT參數 true 圖形界面，false  控制臺輸入
  8  * 2.構造樹是按層次遍歷結果輸入的 如：ABCDE*F**GH
  9  */
 10 
 11 import javax.swing.*;
 12 import java.awt.*;
 13 import java.awt.event.ActionEvent;
 14 import java.awt.event.ActionListener;
 15 import java.io.BufferedReader;
 
 16 import java.io.IOException;
 17 import java.io.InputStreamReader;
 18 
 19 public class BT extends JFrame implements ActionListener {
 20     private BufferedReader br=null;
 21     private MyPanel myPanel;
 22     private JTextField jtf;
 23     private JButton jb1, jb2;
 24     private JLabel jl;
 
 25 
 26     public BT(boolean isGUIMode) {
 27         if (isGUIMode) {
 28             this.setLayout(null); //自定義布局
 29             jtf = new JTextField("");
 30             jtf.setFont(new Font("宋體", Font.BOLD, 16));//Arial
 31             jtf.setColumns(40);
 32             jb1 = new JButton("確定");
 33
 
             jb2 = new JButton("重置");
 34             jb1.setFont(new Font("宋體",Font.PLAIN,16));
 35             jb2.setFont(new Font("宋體",Font.PLAIN,16));//設置按鈕的字體
 36             jl = new JLabel("輸入");
 37             jl.setFont(new Font("華文行楷",Font.PLAIN,20));//設置標簽的字體樣式
 38 
 39             jl.setBounds(35, 20, 50, 50); //如果設置了絕對布局，那麽要通過setBounds()來設置絕對位置與絕對大小
 40             jtf.setBounds(80, 30, 350, 30);
 41             jb1.setBounds(120, 100, 100, 25);
 42             jb2.setBounds(270, 100, 100, 25);
 43             this.add(jl);
 44             this.add(jtf);
 45             this.add(jb1);
 46             this.add(jb2);
 47 
 48             myPanel = new MyPanel();
 49             Thread t = new Thread(myPanel);
 50             t.start();//啟動線程
 51             myPanel.setBounds(0, 150, 3000, 200);//如果沒擋住了的話是不會調用paint方法的
 52             this.add(myPanel);
 53             this.setTitle("BuildTree");
 54             this.setVisible(true);
 55             this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 56             this.setSize(500, 380);
 57             this.setLocation(500, 200);
 58 
 59             jb1.addActionListener(this);//註冊監聽
 60             jb2.addActionListener(this);
 61 
 62         } else {
 63             consoleInput();
 64         }
 65     }
 66 
 67     private void consoleInput() {
 68         br = new BufferedReader(new InputStreamReader(System.in));
 69         System.out.print("Input:");
 70         try {
 71             String input = br.readLine();
 72             while (!input.equals("q")) {
 73                 char[] nodes = input.toCharArray();
 74                 TreeNode treeNode = create(nodes, 0);
 75                 System.out.println("前序：" + displayPreOrder(treeNode));
 76                 System.out.println("中序：" + displayInOrder(treeNode));
 77                 System.out.println("後序：" + displayPostOrder(treeNode));
 78                 System.out.print("Input:");
 79                 input = br.readLine();
 80             }
 81         } catch (IOException e) {
 82             try {
 83                 br.close();
 84             } catch (IOException e1) {
 85                 e1.printStackTrace();
 86             }
 87             e.printStackTrace();
 88         }
 89     }
 90 
 91     private TreeNode create(char[] arr, int index) {
 92         if (index >= arr.length)       // 可以不需要，但是所有的值必須要寫滿，任一個#都要寫，不然會越界
 93             return null;
 94         else if (String.valueOf(arr[index]).equals("#")||String.valueOf(arr[index]).equals("*")) {
 95             return null;
 96         } else {
 97             TreeNode node = new TreeNode(arr[index]);
 98             node.leftChild = create(arr, 2 * index + 1);
 99             node.rightChild = create(arr, 2 * index + 2);
100             return node;
101         }
102     }
103 
104     private static String displayInOrder(TreeNode treeNode) {
105         //中序
106         if (treeNode != null) {
107             return displayInOrder(treeNode.leftChild) + (treeNode.data == ‘*‘ ? "" : treeNode.data) +
108                     displayInOrder(treeNode.rightChild);
109         }
110         return "";
111     }
112 
113     private static String displayPreOrder(TreeNode treeNode) {
114         //前序
115         if (treeNode != null) {
116             return (treeNode.data == ‘*‘ ? "" : treeNode.data) + displayPreOrder(treeNode.leftChild) + displayPreOrder(treeNode.rightChild);
117         }
118         return "";
119     }
120 
121     private static String displayPostOrder(TreeNode treeNode) {
122         //中序
123         if (treeNode != null) {
124             return displayPostOrder(treeNode.leftChild) + displayPostOrder(treeNode.rightChild) + (treeNode.data == ‘*‘ ? "" : treeNode.data);
125         }
126         return "";
127     }
128 
129     @Override
130     public void actionPerformed(ActionEvent e) {
131         if (e.getSource() == jb1) {
132             String s = jtf.getText();
133             if (s.matches("[A-Za-z]([A-Za-z]|\\*|#)*")) {  //註意：是w就可以了，不要用/w,就代表字母下劃線
134                 myPanel.display(s.toCharArray());
135             } else {
136                 JOptionPane.showMessageDialog(null, "輸入錯誤！\n請重試！","ERROR",JOptionPane.ERROR_MESSAGE);
137                 jtf.setText("");
138             }
139         }
140         else if (e.getSource() == jb2) {
141             jtf.setText("");
142         }
143     }
144 
145     public static void main(String[] args) {
146         new BT(true);
147     }
148 
149     class MyPanel extends JPanel implements Runnable {
150         String[] strings;
151 
152         MyPanel() {
153             strings = new String[]{"", "", ""};
154 //            this.setSize(100, 1000);//看來絕對布局裏的setBounds()方法設置的大小具有更高優先級，可以覆蓋這條設置
155             this.setBackground(new Color(125, 134, 234));
156         }
157 
158         public void display(char[] chars) {
159             TreeNode treeNode = create(chars, 0);
160             strings[0] = displayPreOrder(treeNode);
161             strings[1] = displayInOrder(treeNode);
162             strings[2] = displayPostOrder(treeNode);
163         }
164 
165         @Override
166         public void paint(Graphics g) {
167             super.paint(g);//
168             g.setFont(new Font("宋體", Font.BOLD, 24));
169             g.drawString("前序: " + strings[0], 10, 50);
170             g.drawString("中序: " + strings[1], 10, 100);
171             g.drawString("後序: " + strings[2], 10, 150);
172         }
173 
174         @Override
175         public void run() {
176             while (true) {
177                 try {
178                     Thread.sleep(500);
179                     repaint();
180                 } catch (InterruptedException e) {
181                     e.printStackTrace();
182                 }
183             }
184         }
185     }
186 
187     class TreeNode {
188         Character data;
189         TreeNode leftChild;
190         TreeNode rightChild;
191         //含數據，二叉鏈表
192         TreeNode(char data) {
193             this.data = data;
194             leftChild = null;
195             rightChild = null;
196         }
197     }
198 }

層次序創建二叉樹（圖形界面和控制臺輸入實現）