校园导航问题
一、实验任务
设计一个校园导游程序，为来访的客人提供各种信息查询服务。
二、实验要求
（1）设计学校的校园平面图（参考江苏大学校园网上校园平面图或者百度地图），所含景点不少于10个，以图中顶点表示校内各景点，存放景点名称、代号、简介等信息；以边表示路径，存放路径长度等相关信息。
（2）为来访客人提供图中任意景点相关信息的查询。
（3）为来访客人提供景点的问路查询，即已知一个景点，查询到某景点之间的一条最短路径及长度。
三、程序代码
package com.xrw.graph;
import java.util.*;
/**
* @program: DataStructures
* @description: 校园导航问题
* 地图数据来源于百度地图坐标拾取https://api.map.baidu.com/lbsapi/getpoint/index.html
* 将13个景点构造成图，用邻接表结构存储
*
* 功能：
* （1）设计学校的校园平面图（参考江苏大学校园网上校园平面图或者百度地图），所含景点不少于10个，以图中顶点表示校内各景点，存放景点名称、代号、简介等信息；以边表示路径，存放路径长度等相关信息。
*
* （2）为来访客人提供图中任意景点相关信息的查询。
*
* （3）为来访客人提供景点的问路查询，即已知一个景点，查询到某景点之间的一条最短路径及长度。
* @author: 谢荣旺 1429382875@qq.com
* @create: 2021-05-23 18:52
**/
public class CampusNavigation {
public static void main(String[] args) {
/************ 构造邻接表-start **************/
Attraction attraction0 = new Attraction(0,"江苏大学京江操场","体育场地，近京江学院、江苏大学西门"
,"学府路301号江苏大学西门",119.516389,32.211077,null);
Attraction attraction1 = new Attraction(1,"江苏大学F区宿舍","江苏大学学生宿舍F区，近京江学院、江苏大学西门、六食堂，大部分住宿学生为男生"
,"镇江市京口区谷阳路与禹山路交叉路口往东南约100米(江苏大学)",119.516958,32.213999,null);
Attraction attraction2 = new Attraction(2,"江苏大学六食堂","江苏大学第六食堂，近京江学院、江苏大学西门、F区宿舍，六食堂菜式丰富，食物味道可口，并且非常实惠"
,"镇江市京口区学府路301号",119.518984,32.212734,null);
Attraction attraction3 = new Attraction(3,"江苏大学图书馆","江苏大学新图书馆，近江大正门、计算机学院、研究生楼"
,"镇江市京口区学府路301号",119.517791,32.204924,null);
Attraction attraction4 = new Attraction(4,"江苏大学研究生院","江苏大学研究生院，近江大正门、计算机学院、研究生楼，也是疫苗接种点"
,"丹徒路301号江苏大学附近",119.514466,32.203369,null);
Attraction attraction5 = new Attraction(5,"江苏大学三江楼","江苏大学最大也是最著名的授课场所，近江大中门、三山楼、五棵松"
,"镇江市京口区学府路301号",119.525039,32.20211,null);
Attraction attraction6 = new Attraction(6,"江苏大学三山楼","江苏大学第二大的授课场所，通常供高年级同学上课使用，近江大中门、三江楼、五棵松"
,"镇江市京口区学府路301号",119.522016,32.202085,null);
Attraction attraction7 = new Attraction(7,"江苏大学学生工作处","江苏大学学生工作处，位于三山楼和三江楼之间"
,"毓秀路与求实路交叉口西100米",119.52354,32.202582,null);
Attraction attraction8 = new Attraction(8,"江苏大学大礼堂","江苏大学大礼堂，近A区女生宿舍，常用于学术会议、学术活动、文艺演出"
,"镇江市京口区禹山路(江苏大学)",119.523362,32.205959,null);
Attraction attraction9 = new Attraction(9,"江苏大学A区","女生宿舍，近江苏大学大礼堂、西山操场、三食堂"
,"镇江市京口区学府路301号江苏大学A区",119.523031,32.206758,null);
Attraction attraction10 = new Attraction(10,"江苏大学体育馆","体育场地，近江苏大学中门，内设乒乓球场、篮球场、羽毛球场、游泳馆、健身房等"
,"镇江市京口区学府路301号",119.527316,32.200079,null);
Attraction attraction11 = new Attraction(11,"江苏大学西山操场","体育场地，近女生宿舍，位于江苏大学本部校区中间位置"
,"镇江市京口区学府路301号",119.521858,32.206487,null);
Attraction attraction12 = new Attraction(12,"江苏大学东山操场","体育场地，近江苏大学中门、教工宿舍群"
,"镇江市京口区学府路301号",119.527173,32.202735,null);
AttractionGraph graph = new AttractionGraph();
graph.add(attraction0);
graph.add(attraction1);
graph.add(attraction2);
graph.add(attraction3);
graph.add(attraction4);
graph.add(attraction5);
graph.add(attraction6);
graph.add(attraction7);
graph.add(attraction8);
graph.add(attraction9);
graph.add(attraction10);
graph.add(attraction11);
graph.add(attraction12);
graph.get(0).setNext(new GraphNode(1,500,null));
graph.get(0).getNext()
.add(new GraphNode(2,290,null))
.add(new GraphNode(3,920,null))
.add(new GraphNode(4,1100,null))
.add(new GraphNode(5,1700,null))
.add(new GraphNode(6,1400,null))
.add(new GraphNode(7,1600,null))
.add(new GraphNode(8,1300,null))
.add(new GraphNode(9,1200,null))
.add(new GraphNode(10,2200,null))
.add(new GraphNode(11,1100,null))
.add(new GraphNode(12,1900,null));
graph.get(1).setNext(new GraphNode(0,500,null));
graph.get(1).getNext()
.add(new GraphNode(2,420,null))
.add(new GraphNode(3,1300,null))
.add(new GraphNode(4,1500,null))
.add(new GraphNode(5,2000,null))
.add(new GraphNode(6,1800,null))
.add(new GraphNode(7,1700,null))
.add(new GraphNode(8,1500,null))
.add(new GraphNode(9,1300,null))
.add(new GraphNode(10,2400,null))
.add(new GraphNode(11,1200,null))
.add(new GraphNode(12,2100,null));
graph.get(2).setNext(new GraphNode(0,290,null));
graph.get(2).getNext()
.add(new GraphNode(1,420,null))
.add(new GraphNode(3,1100,null))
.add(new GraphNode(4,1300,null))
.add(new GraphNode(5,1600,null))
.add(new GraphNode(6,1400,null))
.add(new GraphNode(7,1300,null))
.add(new GraphNode(8,1100,null))
.add(new GraphNode(9,930,null))
.add(new GraphNode(10,2000,null))
.add(new GraphNode(11,830,null))
.add(new GraphNode(12,1700,null));
graph.get(3).setNext(new GraphNode(0,920,null));
graph.get(3).getNext()
.add(new GraphNode(1,1300,null))
.add(new GraphNode(2,1100,null))
.add(new GraphNode(4,430,null))
.add(new GraphNode(5,990,null))
.add(new GraphNode(6,690,null))
.add(new GraphNode(7,880,null))
.add(new GraphNode(8,840,null))
.add(new GraphNode(9,930,null))
.add(new GraphNode(10,1400,null))
.add(new GraphNode(11,870,null))
.add(new GraphNode(12,1300,null));
graph.get(4).setNext(new GraphNode(0,1100,null));
graph.get(4).getNext()
.add(new GraphNode(1,1500,null))
.add(new GraphNode(2,1300,null))
.add(new GraphNode(3,430,null))
.add(new GraphNode(5,1200,null))
.add(new GraphNode(6,850,null))
.add(new GraphNode(7,1100,null))
.add(new GraphNode(8,1100,null))
.add(new GraphNode(9,1200,null))
.add(new GraphNode(10,1600,null))
.add(new GraphNode(11,1200,null))
.add(new GraphNode(12,1400,null));
graph.get(5).setNext(new GraphNode(0,1700,null));
graph.get(5).getNext()
.add(new GraphNode(1,2000,null))
.add(new GraphNode(2,1600,null))
.add(new GraphNode(3,990,null))
.add(new GraphNode(4,1200,null))
.add(new GraphNode(6,320,null))
.add(new GraphNode(7,240,null))
.add(new GraphNode(8,570,null))
.add(new GraphNode(9,760,null))
.add(new GraphNode(10,330,null))
.add(new GraphNode(11,750,null))
.add(new GraphNode(12,250,null));
graph.get(6).setNext(new GraphNode(0,1400,null));
graph.get(6).getNext()
.add(new GraphNode(1,1800,null))
.add(new GraphNode(2,1400,null))
.add(new GraphNode(3,690,null))
.add(new GraphNode(4,850,null))
.add(new GraphNode(5,320,null))
.add(new GraphNode(7,230,null))
.add(new GraphNode(8,640,null))
.add(new GraphNode(9,730,null))
.add(new GraphNode(10,750,null))
.add(new GraphNode(11,660,null))
.add(new GraphNode(12,570,null));
graph.get(7).setNext(new GraphNode(0,1600,null));
graph.get(7).getNext()
.add(new GraphNode(1,1700,null))
.add(new GraphNode(2,1300,null))
.add(new GraphNode(3,880,null))
.add(new GraphNode(4,1100,null))
.add(new GraphNode(5,240,null))
.add(new GraphNode(6,230,null))
.add(new GraphNode(8,430,null))
.add(new GraphNode(9,620,null))
.add(new GraphNode(10,670,null))
.add(new GraphNode(11,560,null))
.add(new GraphNode(12,460,null));
graph.get(8).setNext(new GraphNode(0,1300,null));
graph.get(8).getNext()
.add(new GraphNode(1,1500,null))
.add(new GraphNode(2,1100,null))
.add(new GraphNode(3,840,null))
.add(new GraphNode(4,1100,null))
.add(new GraphNode(5,570,null))
.add(new GraphNode(6,640,null))
.add(new GraphNode(7,430,null))
.add(new GraphNode(9,180,null))
.add(new GraphNode(10,990,null))
.add(new GraphNode(11,180,null))
.add(new GraphNode(12,680,null));
graph.get(9).setNext(new GraphNode(0,1200,null));
graph.get(9).getNext()
.add(new GraphNode(1,1300,null))
.add(new GraphNode(2,930,null))
.add(new GraphNode(3,930,null))
.add(new GraphNode(4,1200,null))
.add(new GraphNode(5,760,null))
.add(new GraphNode(6,730,null))
.add(new GraphNode(7,620,null))
.add(new GraphNode(8,180,null))
.add(new GraphNode(10,1100,null))
.add(new GraphNode(11,90,null))
.add(new GraphNode(12,780,null));
graph.get(10).setNext(new GraphNode(0,2200,null));
graph.get(10).getNext()
.add(new GraphNode(1,2400,null))
.add(new GraphNode(2,2000,null))
.add(new GraphNode(3,1400,null))
.add(new GraphNode(4,1600,null))
.add(new GraphNode(5,330,null))
.add(new GraphNode(6,750,null))
.add(new GraphNode(7,670,null))
.add(new GraphNode(8,990,null))
.add(new GraphNode(9,1100,null))
.add(new GraphNode(11,1200,null))
.add(new GraphNode(12,400,null));
graph.get(11).setNext(new GraphNode(0,1100,null));
graph.get(11).getNext()
.add(new GraphNode(1,1200,null))
.add(new GraphNode(2,830,null))
.add(new GraphNode(3,870,null))
.add(new GraphNode(4,1200,null))
.add(new GraphNode(5,750,null))
.add(new GraphNode(6,660,null))
.add(new GraphNode(7,560,null))
.add(new GraphNode(8,180,null))
.add(new GraphNode(9,90,null))
.add(new GraphNode(10,1200,null))
.add(new GraphNode(12,860,null));
graph.get(12).setNext(new GraphNode(0,1900,null));
graph.get(12).getNext()
.add(new GraphNode(1,2100,null))
.add(new GraphNode(2,1700,null))
.add(new GraphNode(3,1300,null))
.add(new GraphNode(4,1400,null))
.add(new GraphNode(5,250,null))
.add(new GraphNode(6,570,null))
.add(new GraphNode(7,460,null))
.add(new GraphNode(8,680,null))
.add(new GraphNode(9,780,null))
.add(new GraphNode(10,400,null))
.add(new GraphNode(11,860,null));
/************ 构造邻接表-stop **************/
//接收用户输入
char key = ' ';
//输入流
Scanner scanner = new Scanner(System.in);
Scanner in = new Scanner(System.in);
//控制程序结束的标记
boolean loop = true;
//程序运行，提供一个循环操作给用户
while (loop){
System.out.println("a(all): 显示所有的景点");
System.out.println("s(search): 查询一个景点的详细信息");
System.out.println("p(path): 查询从一个景点到另一个景点的最短路径");
System.out.println("e(exit): 退出程序");
key = scanner.next().charAt(0);//获取用户输入的第一个字符
switch (key){
case 'a':
for (Attraction value : graph) {
System.out.print(value.getName() + "\t");
}
System.out.println();
break;
case 's':
System.out.println("请输入景点的名称：");
String attractionName = scanner.next();
Attraction attractionDetail = graph.searchAttraction(attractionName);
if (attractionDetail != null){
System.out.println(attractionDetail);
break;
}
System.out.println("该景点不存在！");
break;
case 'p':
System.out.println("请输入出发景点的名称：");
String startAttraction = scanner.next();
if (!graph.containsAttraction(startAttraction)){
System.out.println("该景点不存在！");
break;
}
System.out.println("请输入到达景点的名称：");
String stopAttraction = scanner.next();
if (!graph.containsAttraction(stopAttraction)){
System.out.println("该景点不存在！");
break;
}
Map<Attraction,Integer> attractions = graph.shortestPath(startAttraction,stopAttraction);
if (attractions == null){
System.out.println("路径不存在！");
break;
}
attractions.forEach((id,value) -> System.out.println("到达 "+id.getName()+"，需"+value+"米\t"));
System.out.println();
break;
case 'e':
loop = false;
break;
default:
System.out.println("输入非法，请重新输入");
break;
}
}
System.out.println("程序退出~~");
}
}
/**
* @Description: 顶点（景点）集合，集合中每个元素都是一个单链表，代表了从顶点出发能直接到达的相邻顶点
* @Author: 谢荣旺
* @Date: 2021/5/27
*/
class AttractionGraph extends ArrayList<Attraction> {
/**
* @Description: 通过景点名称查询景点是否存在
* @param key: 景点名称
* @return: boolean
* @Author: 谢荣旺
* @Date: 2021/5/27
*/
public boolean containsAttraction(String key){
List<String> attractionNames = new ArrayList<>();
for (Attraction attraction : this){
attractionNames.add(attraction.getName());
}
return attractionNames.contains(key);
}
/**
* 通过出发景点和目的景点查询最短路径 应用迪杰斯特拉（Dijkstra）算法，时间复杂度为O(n^2)
* @param startAttraction 出发景点的名称
* @param stopAttraction 目的景点的名称
* @return
*/
public Map<Attraction,Integer> shortestPath(String startAttraction,String stopAttraction){
//出发景点的编号
int startNo = 0;
//目的景点的编号
int stopNo = 0;
//通过出发景点和目的景点的名称查找他们各自的编号
for (Attraction attraction : this) {
if (attraction.getName().equals(startAttraction)) {
startNo = attraction.getNo();
}
if (attraction.getName().equals(stopAttraction)) {
stopNo = attraction.getNo();
}
}
//辅助集合，存放到达i的最短路径的长度
ArrayList<Integer> dist = new ArrayList<>();
//辅助集合，存放到达i的最短路径的前驱节点
ArrayList<Integer> path = new ArrayList<>();
//辅助集合，标记已经找到最短路径的节点
ArrayList<Integer> s = new ArrayList<>();
//构造初始dis、path、s集合
/************ 构造初始dis、path、s集合-start **************/
//dist中元素默认值为无穷大，表示无法到达
//path中元素默认值为-1，表示无法到达或者出发节点本身
//s中元素默认值为0，表示还未找到最短路径
for(Attraction attraction : this){
dist.add(Integer.MAX_VALUE);
path.add(-1);
s.add(0);
}
//出发节点的dist为0，表示不需要行动就可到达
dist.set(startNo,0);
//从出发节点到他自身不需要再去寻找最短路径，就是他自己，故直接设为1，表示已经找到
s.set(startNo,1);
//辅助指针，用来遍历出发景点的可直接达到的相邻节点
GraphNode temp = this.get(startNo).getNext();
//遍历出发顶点的有向边
while (temp != null) {
//修改可到达的顶点的dist值
dist.set(temp.getNo(), temp.getDistance());
//修改可到达的顶点的path值，即前驱顶点
path.set(temp.getNo(), startNo);
//继续往后遍历
temp = temp.getNext();
}
/************ 构造初始dis、path、s集合-stop **************/
/************ 最短路径的求解-start **************/
//因为出发顶点本身不需要再求最短路径，故只需要遍历this.size()-1次
for (int i = 0; i < this.size()-1; i++) {
int mix = Integer.MAX_VALUE;
int mixIndex = startNo;
//第一次内循环，找出最小的最短路径，并记录最小的最短路径对应的顶点编号和路径长度
for (int j=0;j<dist.size();j++){
if (s.get(j) == 0 && dist.get(j) < mix){
mixIndex = j;
mix = dist.get(j);
}
}
s.set(mixIndex,1);
boolean loop = true;
GraphNode temp2 = this.get(mixIndex).getNext();
//对辅助集合dist和path进行修改，查找出新的最短路径集合
while (temp2 != null) {
if (s.get(temp2.getNo()) == 0 && mix + temp2.getDistance() < dist.get(temp2.getNo())){
dist.set(temp2.getNo(),mix + temp2.getDistance());
path.set(temp2.getNo(),mixIndex);
}
temp2 = temp2.getNext();
}
}
/************ 最短路径的求解-stop **************/
// System.out.println(s);
// System.out.println(dist);
// System.out.println(path);
/************ 通过对辅助数组的查找，将最短路径返回-start **************/
Map<Attraction,Integer> map = new LinkedHashMap<>();
AttractionGraph attractionGraph = new AttractionGraph();
//查找路径，并返回
map.put(this.get(startNo),0);
while (stopNo != startNo){
if (path.get(stopNo) == -1){
return null;
}
attractionGraph.add(this.get(stopNo));
stopNo = path.get(stopNo);
}
//因为是倒序查找的，所以找完之后要将集合的顺序反转
Collections.reverse(attractionGraph);
attractionGraph.forEach(attraction -> map.put(attraction,dist.get(attraction.getNo())));
/************ 通过对辅助数组的查找，将最短路径返回-stop **************/
return map;
}
/**
* @Description: 通过顶点名称查找顶点的详细信息
* @param key: 顶点名称
* @return: com.xrw.graph.Attraction
* @Author: 谢荣旺
* @Date: 2021/5/27
*/
public Attraction searchAttraction(String key){
for (Attraction attraction : this) {
if (attraction.getName().equals(key)) {
return attraction;
}
}
return null;
}
}
/**
* @Description: 有向边对应的顶点编号和有向边的长度
* @Author: 谢荣旺
* @Date: 2021/5/27
*/
class GraphNode{
private int no;
private int distance;
private GraphNode next;
public GraphNode(int no, int distance, GraphNode next) {
this.no = no;
this.distance = distance;
this.next = next;
}
public int getNo() {
return no;
}
public void setNo(int no) {
this.no = no;
}
public int getDistance() {
return distance;
}
public void setDistance(int distance) {
this.distance = distance;
}
public GraphNode getNext() {
return next;
}
public void setNext(GraphNode next) {
this.next = next;
}
public GraphNode add(GraphNode graph) {
GraphNode temp = this;
while (temp.next != null) {
temp = temp.next;
}
temp.next = graph;
return graph;
}
@Override
public String toString() {
return "GraphNode{" +
"no=" + no +
", distance=" + distance +
", next=" + next +
'}';
}
}
/**
* @Description: 顶点对象
* @Author: 谢荣旺
* @Date: 2021/5/27
*/
class Attraction{
private int no;
private String name;
private String introduce;
private String position;
private double longitude;
private double latitude;
private GraphNode next;
public Attraction(int no, String name, String introduce, String position, double longitude, double latitude, GraphNode next) {
this.no = no;
this.name = name;
this.introduce = introduce;
this.position = position;
this.longitude = longitude;
this.latitude = latitude;
this.next = next;
}
public int getNo() {
return no;
}
public void setNo(int no) {
this.no = no;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getIntroduce() {
return introduce;
}
public void setIntroduce(String introduce) {
this.introduce = introduce;
}
public String getPosition() {
return position;
}
public void setPosition(String position) {
this.position = position;
}
public double getLongitude() {
return longitude;
}
public void setLongitude(double longitude) {
this.longitude = longitude;
}
public double getLatitude() {
return latitude;
}
public void setLatitude(double latitude) {
this.latitude = latitude;
}
public GraphNode getNext() {
return next;
}
public void setNext(GraphNode next) {
this.next = next;
}
@Override
public String toString() {
return "Attraction{" +
"no=" + no +
", name='" + name + '\'' +
", introduce='" + introduce + '\'' +
", position='" + position + '\'' +
", longitude=" + longitude +
", latitude=" + latitude +
'}';
}
public String toString2() {
return "Attraction{" +
"no=" + no +
", name='" + name + '\'' +
", introduce='" + introduce + '\'' +
", position='" + position + '\'' +
", longitude=" + longitude +
", latitude=" + latitude +
", next=" + next +
'}';
}
}四、实验结果
五、实验小结
通过这次实验，掌握了图的结构，理解了图的实现原理，将图用领接表的数据结构进行了存储，并且运用迪杰斯特拉算法计算出了从图的一个顶点到另一个顶点的最短路径，极大的强化了我的思维逻辑能力。
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