package algorithm;import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;/*2015-6-26*/
public class FindMinUsefulValue {private static final int MIN = 1;public static void main(String[] args) {List<Integer> list = new ArrayList<Integer>() {private static final long serialVersionUID = 1L;{add(1);add(2);add(5);add(3);add(10);add(100);add(9);}};Collections.sort(list);for (Integer item : list) {System.out.print(item + " ");}System.out.println("Result:" + search(list));}private static int search(List<Integer> list) {int max = list.get(list.size() - 1);if (max == list.size() + MIN - 1) {return max + 1;}int targetNum = MIN;for (int i = 0; i < list.size(); i++) {targetNum = MIN + i;if (list.get(i) == MIN + i) {continue;}break;}return targetNum;}/*** 查找最接近目標值的數，并返回* * @param array* @param targetNum* @return*/public static Integer binarysearchKey(Object[] array, int targetNum) {Arrays.sort(array);int targetindex = 0;int left = 0, right = 0;for (right = array.length - 1; left != right;) {int midIndex = (right + left) / 2;int mid = (right - left);int midValue = (Integer) array[midIndex];if (targetNum == midValue) {return midIndex;}if (targetNum > midValue) {left = midIndex;} else {right = midIndex;}if (mid <= 2) {break;}}System.out.println("和要查找的數：" + targetNum + "最接近的數："+ array[targetindex]);return (Integer) (((Integer) array[right] - (Integer) array[left]) / 2 > targetNum ? array[right]: array[left]);}
}
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Output:
1 2 3 5 9 10 100 Result:4
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Tutorials上的一個Sample:
package misc;import java.awt.*;
import java.awt.event.*;import java.util.Vector;import javax.swing.*;/** FocusTraversalDemo.java requires no other files.*/publicclass FocusTraversalDemo extends JPanelimplements ActionListener {static JFrame frame;JLabel label;JCheckBox togglePolicy;static MyOwnFocusTraversalPolicy newPolicy;public FocusTraversalDemo() {super(new BorderLayout());JTextField tf1 = new JTextField("Field 1");JTextField tf2 = new JTextField("A Bigger Field 2");JTextField tf3 = new JTextField("Field 3");JTextField tf4 = new JTextField("A Bigger Field 4");JTextField tf5 = new JTextField("Field 5");JTextField tf6 = new JTextField("A Bigger Field 6");JTable table = new JTable(4,3);togglePolicy = new JCheckBox("Custom FocusTraversalPolicy");togglePolicy.setActionCommand("toggle");togglePolicy.addActionListener(this);togglePolicy.setFocusable(false); //Remove it from the focus cycle.//Note that HTML is allowed and will break this run of text//across two lines.label = new JLabel("<html>Use Tab (or Shift-Tab) to navigate from component to component.<p>Control-Tab (or Control-Shift-Tab) allows you to break out of the JTable.</html>");JPanel leftTextPanel = new JPanel(new GridLayout(3,2));leftTextPanel.add(tf1, BorderLayout.PAGE_START);leftTextPanel.add(tf3, BorderLayout.CENTER);leftTextPanel.add(tf5, BorderLayout.PAGE_END);leftTextPanel.setBorder(BorderFactory.createEmptyBorder(0,0,5,5));JPanel rightTextPanel = new JPanel(new GridLayout(3,2));rightTextPanel.add(tf2, BorderLayout.PAGE_START);rightTextPanel.add(tf4, BorderLayout.CENTER);rightTextPanel.add(tf6, BorderLayout.PAGE_END);rightTextPanel.setBorder(BorderFactory.createEmptyBorder(0,0,5,5));JPanel tablePanel = new JPanel(new GridLayout(0,1));tablePanel.add(table, BorderLayout.CENTER);tablePanel.setBorder(BorderFactory.createEtchedBorder());JPanel bottomPanel = new JPanel(new GridLayout(2,1));bottomPanel.add(togglePolicy, BorderLayout.PAGE_START);bottomPanel.add(label, BorderLayout.PAGE_END);add(leftTextPanel, BorderLayout.LINE_START);add(rightTextPanel, BorderLayout.CENTER);add(tablePanel, BorderLayout.LINE_END);add(bottomPanel, BorderLayout.PAGE_END);setBorder(BorderFactory.createEmptyBorder(20,20,20,20));Vector<Component> order = new Vector<Component>(7);order.add(tf1);order.add(tf2);order.add(tf3);order.add(tf4);order.add(tf5);order.add(tf6);order.add(table);newPolicy = new MyOwnFocusTraversalPolicy(order);}//Turn the custom focus traversal policy on/off,//according to the checkboxpublicvoid actionPerformed(ActionEvent e) {if ("toggle".equals(e.getActionCommand())) {frame.setFocusTraversalPolicy(togglePolicy.isSelected() ?newPolicy : null);}}/*** Create the GUI and show it. For thread safety,* this method should be invoked from the* event-dispatching thread.*/privatestaticvoid createAndShowGUI() {//Create and set up the window.frame = new JFrame("FocusTraversalDemo");frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//Create and set up the content pane.JComponent newContentPane = new FocusTraversalDemo();newContentPane.setOpaque(true); //content panes must be opaque frame.setContentPane(newContentPane);//Display the window. frame.pack();frame.setVisible(true);}publicstaticvoid main(String[] args) {/* Use an appropriate Look and Feel */try {//UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");//UIManager.setLookAndFeel("com.sun.java.swing.plaf.gtk.GTKLookAndFeel");UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");} catch (UnsupportedLookAndFeelException ex) {ex.printStackTrace();} catch (IllegalAccessException ex) {ex.printStackTrace();} catch (InstantiationException ex) {ex.printStackTrace();} catch (ClassNotFoundException ex) {ex.printStackTrace();}/* Turn off metal's use of bold fonts */UIManager.put("swing.boldMetal", Boolean.FALSE);//Schedule a job for the event-dispatching thread://creating and showing this application's GUI.javax.swing.SwingUtilities.invokeLater(new Runnable() {publicvoid run() {createAndShowGUI();}});}publicstaticclass MyOwnFocusTraversalPolicyextends FocusTraversalPolicy{Vector<Component> order;public MyOwnFocusTraversalPolicy(Vector<Component> order) {this.order = new Vector<Component>(order.size());this.order.addAll(order);}public Component getComponentAfter(Container focusCycleRoot,Component aComponent){int idx = (order.indexOf(aComponent) + 1) % order.size();return order.get(idx);}public Component getComponentBefore(Container focusCycleRoot,Component aComponent){int idx = order.indexOf(aComponent) - 1;if (idx < 0) {idx = order.size() - 1;}return order.get(idx);}public Component getDefaultComponent(Container focusCycleRoot) {return order.get(0);}public Component getLastComponent(Container focusCycleRoot) {return order.lastElement();}public Component getFirstComponent(Container focusCycleRoot) {return order.get(0);}}
}
import java.awt.*;import java.util.*;import java.awt.event.*;import javax.swing.*;// This program demonstrates the use of the Swing InputVerifier class.// It creates two text fields; the first of the text fields expects the// string "pass" as input, and will allow focus to advance out of it// only after that string is typed in by the user.publicclass VerifierTest extends JFrame {public VerifierTest() {JTextField tf1 = new JTextField ("Type \"pass\" here");getContentPane().add (tf1, BorderLayout.NORTH);tf1.setInputVerifier(new PassVerifier());JTextField tf2 = new JTextField ("TextField2");getContentPane().add (tf2, BorderLayout.SOUTH);WindowListener l = new WindowAdapter() {publicvoid windowClosing(WindowEvent e) { System.exit(0); }};addWindowListener(l);}class PassVerifier extends InputVerifier {publicboolean verify(JComponent input) {JTextField tf = (JTextField) input;return "pass".equals(tf.getText());}}publicstaticvoid main(String[] args) {Frame f = new VerifierTest();f.pack();f.setVisible(true);}}
