java求解N皇后问题代码及答案

实验题目 回溯法 n 皇后问题 班级 信息 112姓名 孙波学号 110111213日期 2014 5 13 一 实验目的 会用回溯法求解 n 皇后问题 通过实验掌握如何使用回溯法求解问题 二 实验要求 用自己熟悉的高级程序设计语言编写程序实现求解 n 皇后问题的回溯算法 使用剪枝函数来避免不必要的搜索 三 源程序 带注释 import java applet Applet import java awt BorderLayout import java awt Color import java awt Container import java awt Graphics import java awt Graphics2D import java awt GridLayout import java awt TextArea import java awt Toolkit import java awt event ActionEvent import java awt event ActionListener import java awt event ItemEvent import java awt event ItemListener import java awt event WindowAdapter import java awt event WindowEvent import java util Hashtable import javax swing BorderFactory import javax swing ButtonGroup import javax swing JButton import javax swing JFrame import javax swing JLabel import javax swing JPanel import javax swing JRadioButton import javax swing JScrollPane import javax swing JSlider import javax swing JTextField import javax swing event ChangeEvent import javax swing event ChangeListener public class NQueen implements ItemListener ActionListener ChangeListener JFrame f new JFrame N QUEEN PROBLEM DEMO Container cp f getContentPane int x new int 10 int X new int 10000 10 String str new String 10000 int m 4 a 1 b 1 counter 0 j 1 Panel4 panel4 new Panel4 TextArea t1 new TextArea 30 40 JTextField t2 new JTextField 10 JRadioButton r1 new JRadioButton 4个 JRadioButton r2 new JRadioButton 5个 JRadioButton r3 new JRadioButton 6个 JRadioButton r4 new JRadioButton 7个 JRadioButton r5 new JRadioButton 8个 JButton button1 new JButton 开始演示 JButton button2 new JButton 暂停 JButton button3 new JButton 清空 JSlider slider1 new JSlider 20 100 javax swing Timer timer1 窗口的布局 public NQueen cp setLayout new BorderLayout 20 20 t2 setBorder BorderFactory createTitledBorder 解的个数 JScrollPane scrollPane1 new JScrollPane t1 scrollPane1 setBorder BorderFactory createTitledBorder 展示所有解 JPanel panel1 new JPanel panel1 setLayout new GridLayout 2 1 10 20 JPanel panel2 new JPanel panel2 setLayout new GridLayout 6 1 panel2 setBorder BorderFactory createTitledBorder 请选择 皇后的个数 JPanel panel3 new JPanel panel3 setLayout new GridLayout 4 1 10 10 r1 addItemListener this r2 addItemListener this r3 addItemListener this r4 addItemListener this r5 addItemListener this button1 addActionListener this button2 addActionListener this button3 addActionListener this slider1 setPaintTicks true slider1 setMajorTickSpacing 40 slider1 setMinorTickSpacing 20 slider1 setPaintLabels true slider1 setPaintTrack true slider1 setSnapToTicks true slider1 addChangeListener this slider1 setBorder BorderFactory createTitledBorder 调节 演示的速度 timer1 new javax swing Timer slider1 getValue 25 this Hashtable table new Hashtable table put new Integer 20 new JLabel 快 table put new Integer 100 new JLabel 慢 slider1 setLabelTable table ButtonGroup buttong1 new ButtonGroup buttong1 add r1 buttong1 add r2 buttong1 add r3 buttong1 add r4 buttong1 add r5 panel1 add panel2 panel1 add panel3 panel2 add r1 panel2 add r2 panel2 add r3 panel2 add r4 panel2 add r5 panel2 add t2 panel3 add button1 panel3 add button2 panel3 add button3 panel3 add slider1 cp add panel1 BorderLayout WEST cp add panel4 BorderLayout CENTER cp add scrollPane1 BorderLayout EAST f setSize 865 600 f setVisible true f addWindowListener new WindowAdapter public void windowClosing WindowEvent e System exit 0 N皇后算法 public void nqueen int n int k x 1 0 k 1 for int i 0 i0 while x k n if x k n if k n counter for int i 1 i n i X a i x i str a str a x i a System out print n else k k 1 x k 0 else k k 1 return 判断皇后位置的合法性 public boolean place int b int k b i 1 while i k if x i x k Math abs x i x k Math abs i k return false i i 1 return true 主方法 param args public static void main String args new NQueen TODO Auto generated method stub 画棋盘和皇后的位置 SuppressWarnings serial public class Panel4 extends Applet public void paint Graphics g super paint g Graphics2D g2 Graphics2D g g2 setColor Color white g2 fillRect 0 0 500 600 g setColor Color black for int i 0 i m i g2 drawLine i 240 m 20 20 i 240 m 20 260 g2 drawLine 20 i 240 m 20 260 i 240 m 20 g2 setColor Color blue for int i 1 i m i g2 drawString Q 30 X j i 1 240 m 10 i 240 m 皇后个数的选择 SuppressWarnings static access Override public void itemStateChanged ItemEvent e if e getStateChange e SELECTED if e getSource r1 m 4 a 1 b 1 j 1 counter 0 nqueen m t2 setText counter panel4 repaint System out print m if e getSource r2 m 5 a 1 b 1 j 1 counter 0 nqueen m t2 setText counter panel4 repaint System out print m if e getSource r3 m 6 a 1 b 1 j 1 counter 0 nqueen m t2 setText counter panel4 repaint System out print m if e getSource r4 m 7 a 1 b 1 j 1 counter 0 nqueen m t2 setText counter panel4 repaint System out print m if e getSource r5 m 8 a 1 b 1 j 1 counter 0 nqueen m t2 setText counter panel4 repaint System out print m TODO Auto generated method stub 按钮功能的实现 Override public void actionPerformed ActionEvent e if e getSource button1 j 0 timer1 start Toolkit getDefaultToolkit beep if e getSource button2 timer1 stop Toolkit getDefaultToolkit beep if e getSource button3 timer1 stop t1 setText b 1 Toolkit getDefaultToolkit beep if e ge