1 2018.11.7

2 XT3

4 /**

5 * 功能：构造二叉树6 * 说明：7 * 1.主函数输入模式有两种，BT参数 true 图形界面，false 控制台输入8 * 2.构造树是按层次遍历结果输入的 如：ABCDE*F**GH9 */

10

11 import javax.swing.*;12 import java.awt.*;13 importjava.awt.event.ActionEvent;14 importjava.awt.event.ActionListener;15 importjava.io.BufferedReader;16 importjava.io.IOException;17 importjava.io.InputStreamReader;18

19 public class BT extends JFrame implementsActionListener {20 private BufferedReader br=null;21 privateMyPanel myPanel;22 privateJTextField jtf;23 privateJButton jb1, jb2;24 privateJLabel jl;25

26 public BT(booleanisGUIMode) {27 if(isGUIMode) {28 this.setLayout(null); //自定义布局

29 jtf = new JTextField("");30 jtf.setFont(new Font("宋体", Font.BOLD, 16));//Arial

31 jtf.setColumns(40);32 jb1 = new JButton("确定");33 jb2 = new JButton("重置");34 jb1.setFont(new Font("宋体",Font.PLAIN,16));35 jb2.setFont(new Font("宋体",Font.PLAIN,16));//设置按钮的字体

36 jl = new JLabel("输入");37 jl.setFont(new Font("华文行楷",Font.PLAIN,20));//设置标签的字体样式

38

39 jl.setBounds(35, 20, 50, 50); //如果设置了绝对布局，那么要通过setBounds()来设置绝对位置与绝对大小

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 = newMyPanel();49 Thread t = newThread(myPanel);50 t.start();//启动线程

51 myPanel.setBounds(0, 150, 3000, 200);//如果没挡住了的话是不会调用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);//注册监听

60 jb2.addActionListener(this);61

62 } else{63 consoleInput();64 }65 }66

67 private voidconsoleInput() {68 br = new BufferedReader(newInputStreamReader(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("后序：" +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, intindex) {92 if (index >= arr.length) //可以不需要，但是所有的值必须要写满，任一个#都要写，不然会越界

93 return null;94 else if (String.valueOf(arr[index]).equals("#")||String.valueOf(arr[index]).equals("*")) {95 return null;96 } else{97 TreeNode node = newTreeNode(arr[index]);98 node.leftChild = create(arr, 2 * index + 1);99 node.rightChild = create(arr, 2 * index + 2);100 returnnode;101 }102 }103

104 private staticString 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 staticString 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 staticString 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 @Override130 public voidactionPerformed(ActionEvent e) {131 if (e.getSource() ==jb1) {132 String s =jtf.getText();133 if (s.matches("[A-Za-z]([A-Za-z]|\\*|#)*")) { //注意：是w就可以了，不要用/w,就代表字母下划线

134 myPanel.display(s.toCharArray());135 } else{136 JOptionPane.showMessageDialog(null, "输入错误！\n请重试！","ERROR",JOptionPane.ERROR_MESSAGE);137 jtf.setText("");138 }139 }140 else if (e.getSource() ==jb2) {141 jtf.setText("");142 }143 }144

145 public static voidmain(String[] args) {146 new BT(true);147 }148

149 class MyPanel extends JPanel implementsRunnable {150 String[] strings;151

152 MyPanel() {153 strings = new String[]{"", "", ""};154 //this.setSize(100, 1000);//看来绝对布局里的setBounds()方法设置的大小具有更高优先级，可以覆盖这条设置

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 @Override166 public voidpaint(Graphics g) {167 super.paint(g);//168 g.setFont(new Font("宋体", Font.BOLD, 24));169 g.drawString("前序: " + strings[0], 10, 50);170 g.drawString("中序: " + strings[1], 10, 100);171 g.drawString("后序: " + strings[2], 10, 150);172 }173

174 @Override175 public voidrun() {176 while (true) {177 try{178 Thread.sleep(500);179 repaint();180 } catch(InterruptedException e) {181 e.printStackTrace();182 }183 }184 }185 }186

187 classTreeNode {188 Character data;189 TreeNode leftChild;190 TreeNode rightChild;191 //含数据，二叉链表

192 TreeNode(chardata) {193 this.data =data;194 leftChild = null;195 rightChild = null;196 }197 }198 }