Question

求程序代码（java版的数据结构）

我正在学习数据结构，学到图这一章了，现在要写实验报告，明天要交，但是我没有题目的代码，但又写不出来，希望会的人能够留下你们的代码，感谢！！！
题目如下：
1.判断一个图中指定的两点之间是否存在一条路径，若存在，求出最短路径。
2.判断一个图中指定的一条路径是否为回路。

最好能同时给出思想啊，谢谢了。。。。。

Answer 1

3个class，运行UI.java。
******
public class CircuitException extends Exception {public CircuitException(){}}
*****
import java.util.LinkedList;
public class GPS {
public static final int MAX = 65535;
public GPS(int maxSize){
graph = new Graph(maxSize);
}
public GPS(){
graph = new Graph();
}
public Graph graph;
public static void main(String args[]){
GPS gps = new GPS();
try {
gps.graph.addEdge("a", "b", 1);
gps.graph.addEdge("a", "c", 1);
gps.graph.addEdge("b","d" , 1);
gps.graph.addEdge("c","d" , 1);
gps.graph.addEdge("d","e" , 1);
gps.graph.addEdge("d","f" , 1);
gps.graph.addEdge("e","t" , 2);
gps.graph.addEdge("f","t" , 1);
LinkedList list = gps.graph.getPath("a", "d");
for(int i = 0 ; i < list.size() ; i++){
System.out.print(list.get(i));

}System.out.println();
} catch (CircuitException e) {
System.out.println("出现了自环！");
}
gps.graph.showGraph();
System.out.println(gps.graph.gap);
}
public class Graph{
public int Zuidazhi = 50;
public int changdu = 0;
public Jiao[] vertex;
public double gap;
public Graph(){
vertex = new Jiao[Zuidazhi];
}
public Graph(int maxSize){
this.Zuidazhi = maxSize;
vertex = new Jiao[maxSize];
}
public void addVertex(String name){
vertex[changdu++] = new Jiao(name);
}
public void addEdge(String v1, String v2,double edge) throws CircuitException{
//先找到v1；
if(v1.equals(v2))
throw new CircuitException();
Jiao from = null;
Jiao to = null;
for(int i = 0 ; i < changdu ; i++){
if(vertex[i].name.equals(v1)){
from = vertex[i];
}else if(vertex[i].name.equals(v2)){
to = vertex[i];
}
}
if(from == null){
this.addVertex(v1);
from = this.vertex[changdu-1];
}
if(to == null){
this.addVertex(v2);
to = this.vertex[changdu-1];
}//已经找到v1和v2；
//没有检测是否v1 v2边已经存在！
//加入边。
Jiao v1adj = new Jiao(v2);
v1adj.edge = edge;
Jiao v2adj = new Jiao(v1);
v2adj.edge = edge;
//添加联系
//检查联系是否已经存在
Jiao temp = from;
while(temp.next!=null){
Jiao temppar = temp;
temp = temp.next;
if(temp.name.equals(v1adj.name)){
temppar.next = temp.next;
}
}
v1adj.next = from.next;
from.next = v1adj;
//v2adj.next = to.next;
//to.next = v2adj;
}
//假设要找的必然存在，不用想是否不在
public LinkedList getPath(String v1 ,String v2){
int count = 0;
//System.out.println(count++);
boolean found[] = new boolean[changdu];
double distance[] = new double[changdu];
int to = 0;
Jiao from = null;
for(int i = 0 ; i < changdu ; i++){
found[i] = false;
distance[i] = MAX;
}
for(int i = 0 ; i < changdu ; i++){
if(vertex[i].name.equals(v1)){//找到始发地
from = vertex[i];
distance[i] = 0;
found[i] = true;
//System.out.println(count++);
}
if(vertex[i].name.equals(v2)){//找到目的地
to = i;
//System.out.println(count++);
}
}
//必须先准备好路径！
Jiao forCount = from;
int degree = 0;
while(forCount!=null){
degree++;
forCount=forCount.next;
}
LinkedList[] list = new LinkedList[degree];
int [] mark = new int[degree];
for(int i = 0 ; i < degree ; i++){
list[i]=new LinkedList();
mark[i]=MAX;
}
int test=0;
int count2 = 0;
int count3 = 0;
//System.out.println(count+++"xx");
while(!found[to]&&test++<100){
//System.out.println(count+++"FIRST");

//开始时from到所有都是最大值。
//找到标记了的节点
//找标记了的节点邻接的未标记的节点。
//得到最短的边，并标记。
//更新现有路径
double min = MAX;
int address = -1;
int father = -1;
for(int i = 0 ; i < changdu ; i++){//对于已经找到的顶点寻找最小的往后的距离。
if(found[i]){//找到了的。
Jiao temp = vertex[i];
while(temp!=null){//vertex的邻接顶点~~

//先看temp的号码~
int tempNumber = -1;
for(int j = 0 ; j < changdu ; j++){
if(vertex[j].name.equals(temp.name)){
tempNumber = j;
break;
}
}
if(!found[tempNumber]){//如果是还没有找到的~
double dist = distance[i]+temp.edge;
if(dist < min){
min = dist;
father = i;
//System.out.println(" "+min);
address = tempNumber;
}
}
temp = temp.next;
}

}

}found[address] = true;
distance[address] = min;
//添加到已有路径中去！
//知道father
for(int i = 0 ; i < degree ; i++){
if(list[i].isEmpty()||list[i].getLast().equals(vertex[father].name)){
list[i].addLast(vertex[address].name);
break;
}
}
}
for(int i = 0 ; i < degree ; i++){
if(list[i].isEmpty())
continue;
else{
if(list[i].getLast().equals(v2)){
gap=0;
//先求出gap
Jiao pre = from;
Jiao nex = null;
for(int j = 0 ; j < list[i].size() ; j++){
for(int k = 0 ; k < changdu ; k++){
if(vertex[k].name.equals(list[i].get(j))){
nex = vertex[k];break;
}
}

while(pre.next!=null){//找到下一个的长度
pre = pre.next;
//System.out.println(nex.name +"nex.name");
if(pre.name.equals(nex.name)){
gap+=pre.edge;
//System.out.println(" gap2 "+gap);
}
}
pre = nex;
}
//System.out.println(gap+"gap");
return list[i];
}
}
}
return null;
}
public void showGraph(){
Jiao temp;
for(int i = 0 ; i < changdu ; i++){
temp = vertex[i];
while(temp!=null){
System.out.print(temp.name+temp.edge+" ");
temp = temp.next;
}System.out.println();
}System.out.println("Show Over!");
}
}

public class Jiao{
public String name;
public Jiao next = null;
public double edge;
public Jiao(String name){
this.name = name;
}
}
}
******
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.LinkedList;
import javax.swing.JButton;
import javax.swing.DefaultListModel;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JOptionPane;
import javax.swing.JScrollPane;
import javax.swing.JSeparator;
import javax.swing.JTextField;
import javax.swing.SwingConstants;

public class UI extends JFrame implements ActionListener{

private JTextField textField_5;
private JTextField textField_4;
private JList list_1;
private JList list;
private JTextField textField_1;
private JTextField textField_3;
private JTextField textField_2;
private JTextField textField;
private DefaultListModel model = new DefaultListModel();
private DefaultListModel model_1 = new DefaultListModel();
/**
* Launch the application
* @param args
*/
public static void main(String args[]) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
UI frame = new UI();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}

/**
* Create the frame
*/
public UI() {
super();
setTitle("GPS寻路");
getContentPane().setLayout(null);
setBounds(100, 100, 500, 375);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

final JScrollPane scrollPane = new JScrollPane();
scrollPane.setBounds(11, 36, 221, 193);
getContentPane().add(scrollPane);

list = new JList(model);
scrollPane.setViewportView(list);

final JScrollPane scrollPane_1 = new JScrollPane();
scrollPane_1.setBounds(253, 36, 218, 193);
getContentPane().add(scrollPane_1);

list_1 = new JList(model_1);
scrollPane_1.setViewportView(list_1);

final JLabel label = new JLabel();
label.setText("从");
label.setBounds(10, 249, 24, 18);
getContentPane().add(label);

final JLabel label_1 = new JLabel();
label_1.setText("到");
label_1.setBounds(11, 273, 24, 18);
getContentPane().add(label_1);

textField = new JTextField();
textField.setBounds(50, 247, 103, 22);
getContentPane().add(textField);

textField_2 = new JTextField();
textField_2.setBounds(50, 271, 103, 22);
getContentPane().add(textField_2);

final JLabel label_2 = new JLabel();
label_2.setText("距离");
label_2.setBounds(11, 297, 37, 18);
getContentPane().add(label_2);

textField_3 = new JTextField();
textField_3.setBounds(50, 295, 103, 22);
getContentPane().add(textField_3);

final JButton button = new JButton();
button.setText("添加");
button.setBounds(155, 250, 73, 28);
getContentPane().add(button);

final JButton button_1 = new JButton();
button_1.setText("删除");
button_1.setBounds(155, 285, 73, 28);
getContentPane().add(button_1);

final JLabel label_3 = new JLabel();
label_3.setText("距离：");
label_3.setBounds(253, 297, 39, 18);
getContentPane().add(label_3);

textField_1 = new JTextField();
textField_1.setBounds(293, 295, 86, 22);
getContentPane().add(textField_1);

final JButton button_2 = new JButton();
button_2.setText("显示路径");
button_2.setBounds(385, 249, 86, 68);
getContentPane().add(button_2);

final JLabel label_4 = new JLabel();
label_4.setText("路径表示");
label_4.setBounds(11, 10, 66, 18);
getContentPane().add(label_4);

final JLabel label_5 = new JLabel();
label_5.setText("最佳路径");
label_5.setBounds(253, 12, 66, 18);
getContentPane().add(label_5);
//
button.addActionListener(this);
button_1.addActionListener(this);
button_2.addActionListener(this);

final JLabel label_6 = new JLabel();
label_6.setText("从");
label_6.setBounds(253, 249, 24, 18);
getContentPane().add(label_6);

textField_4 = new JTextField();
textField_4.setBounds(293, 247, 86, 22);
getContentPane().add(textField_4);

final JLabel label_7 = new JLabel();
label_7.setText("到");
label_7.setBounds(253, 273, 24, 18);
getContentPane().add(label_7);

textField_5 = new JTextField();
textField_5.setBounds(293, 271, 86, 22);
getContentPane().add(textField_5);

final JSeparator separator = new JSeparator();
separator.setOrientation(SwingConstants.VERTICAL);
separator.setBounds(239, 10, 8, 317);
getContentPane().add(separator);
}

@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
if(e.getActionCommand().equals("添加")){

try{String from = textField.getText();
String to = textField_2.getText();
if(from.equals(to)){
JOptionPane.showMessageDialog(null, "始点与终点不能相同");
return;
}
if(from.equals("")||to.equals("")){
JOptionPane.showMessageDialog(null, "添加不能为空");
return;
}for(int i = 0 ; i < model.size() ; i ++){
if(model.get(i).toString().substring(0, model.get(i).toString().indexOf(":")).equals(
from+"->"+to))
model.remove(i);
}
double length = Double.parseDouble(textField_3.getText());
model.addElement(from+"->"+to+": "+length);

}catch(Exception e1){
JOptionPane.showMessageDialog(null, "距离为数字值");
}
}
if(e.getActionCommand().equals("删除")){
for(int i = 0 ; i < model.size() ; i++){
if(list.isSelectedIndex(i))
model.remove(i);
}
}
if(e.getActionCommand().equals("显示路径")){
try{
model_1.removeAllElements();
GPS gps = new GPS();
String full,from,to;
double length;
for(int i = 0 ; i < model.size() ; i++){
full = model.get(i).toString();
from = full.substring(0,full.indexOf("-"));
to = full.substring(full.indexOf("-")+2,full.lastIndexOf(":"));
length = Double.parseDouble(full.substring(full.indexOf(":")+1, full.length()-1));
//System.out.println(from);
//System.out.println(to);
try {
gps.graph.addEdge(from, to, length);
System.out.println(from +" "+ to);
} catch (CircuitException e1) {
System.out.println("有环存在");
}
}LinkedList list = gps.graph.getPath(textField_4.getText(), textField_5.getText());
model_1.addElement(textField_4.getText());
for(int i = 0 ; i < list.size() ; i++){
model_1.addElement(list.get(i));
}//计算路径长度
textField_1.setText(""+gps.graph.gap);
}catch(Exception e1){
JOptionPane.showMessageDialog(null, "没有找到有关节点");
}
}
}
}