实现功能：main函数及相关函数
未实现：dijkstra算法相关内容
Github地址：https://github.com/liangshuwei777/sub
一、实现功能
1、查询地铁线路
2、查询最短地铁换乘路径
二、使用语言
java
三、主要算法
dijkstra算法
四、实现代码
1、地图信息
2、将sub.txt的地图路线信息导入
public static void read(){ DistanceBuilder.FILE_PATH=System.getProperty("user.dir") + File.separator + "\\" +"sub.txt";
DistanceBuilder.readSubway();
}
public static void readSubway() {
File file = new File(FILE_PATH);
BufferedReader reader = null;
try {
InputStreamReader inputStreamReader = new InputStreamReader(new FileInputStream(file),"UTF-8");
reader = new BufferedReader(inputStreamReader);
String line = null;
String lineName = "1"; //默认起始为1号线
distanceMap.put("1",new HashMap<>());
while ((line = reader.readLine()) != null) {
if(line.trim().length()==1||line.trim().length()==3||line.trim().length()==2){
if(line.trim().length()==3||line.trim().length()==2){
continue;
}
lineName = line;
if(!distanceMap.keySet().contains(line)){
distanceMap.put(line.trim(),new HashMap<>());
}
}else{
if(line.trim().startsWith("*")){
String[] lineInfo = line.substring(1).split("-");
lineSet.add(getLine(lineInfo[1].trim(),lineInfo[0].trim()));
}
else{
String texts[] = line.split("\t");
String key = texts[0].trim();
Double value = Double.valueOf(texts[1]);
distanceMap.get(lineName).put(key,value);
String other = key.split(":")[1].trim()+":"+key.split(":")[0].trim();
distanceMap.get(lineName).put(other,value);
}
}
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (FileNotFoundException e) {
e.printStackTrace();
}catch (IOException e) {
e.printStackTrace();
} finally {
}
}
3、dijkstra算法
public class DijkstraUtil {
private static HashMap resultMap = new HashMap<>();
private static List analysisList = new ArrayList<>();
public static Result calculate(Station star, Station end) { //dijkstra算法
if (!analysisList.contains(star)) {
analysisList.add(star);
}
if (star.equals(end)) {
Result result = new Result();
result.setDistance(0.0D);
result.setEnd(star);
result.setStar(star);
return resultMap.put(star, result);
}
if (resultMap.isEmpty()) {
List linkStations = getLinkStations(star); //第一次调用获取起始点的相邻站点
for (Station station : linkStations) { //把相邻站点集合中的所有站点，加入resultMap中
Result result = new Result();
result.setStar(star);
result.setEnd(station);
String key = star.getName() + ":" + station.getName();
Double distance = DistanceBuilder.getDistance(key);
result.setDistance(distance);
result.getPassStations().add(station);
resultMap.put(station, result);
}
}
Station parent = getNextStation();
if (parent == null) {
Result result = new Result();
result.setDistance(0.0D);
result.setStar(star);
result.setEnd(end);
return resultMap.put(end, result);
}
if (parent.equals(end)) {
return resultMap.get(parent);
}
List childLinkStations = getLinkStations(parent);
for (Station child : childLinkStations) {
if (analysisList.contains(child)) {
continue;
}
String key = parent.getName() + ":" + child.getName();
Double distance;
distance = DistanceBuilder.getDistance(key);
DistanceBuilder.getDistance(key);
if (parent.getName().equals(child.getName())) {
distance = 0.0D;
}
Double parentDistance = resultMap.get(parent).getDistance();
distance = doubleAdd(distance, parentDistance);
List parentPassStations = resultMap.get(parent).getPassStations();
Result childResult = resultMap.get(child);
if (childResult != null) {
if (childResult.getDistance() > distance) {
childResult.setDistance(distance);
childResult.getPassStations().clear();
childResult.getPassStations().addAll(parentPassStations);//路线更新
childResult.getPassStations().add(child);
}
} else {
childResult = new Result();
childResult.setDistance(distance);
childResult.setStar(star);
childResult.setEnd(child);
childResult.getPassStations().addAll(parentPassStations);
childResult.getPassStations().add(child);
}
resultMap.put(child, childResult);
}
analysisList.add(parent);
calculate(star, end);
return resultMap.get(end);
}
private static List getLinkStations(Station station) { // 获取所有相邻节点.
List linkedStaions = new ArrayList();
for (List line : DistanceBuilder.lineSet) { //遍历所有地铁线
for (int i = 0; i < line.size(); i++) {
if (station.equals(line.get(i))) {
if (i == 0) {
linkedStaions.add(line.get(i + 1));//地铁站为换乘线的初始站，则继续+1遍历
} else if (i == (line.size() - 1)) {
linkedStaions.add(line.get(i - 1));//地铁站为换乘线的终点站，则继续-1遍历
} else {
linkedStaions.add(line.get(i + 1));
linkedStaions.add(line.get(i - 1));
}
}
}
}
return linkedStaions;
}
3、主函数与站点、结果存储见github
4、输出路线所有站点、最佳路径
public static void writeLineData(String lineName){
createlineData();
lineName = lineName.substring(0,3);
List lineInfo = lineData.get(lineName);
//System.out.println(lineData.get(lineName));
String lineStr = lineInfo.stream().map(x->x.getName()).collect(Collectors.joining(",","[","]"));
System.out.print(lineStr);
}
public static void getPassStation(Result result){
//System.out.print(result.getStar());
String starLine = getLineNameByStation(result.getStar());
String converLine = starLine;
System.out.println("起始地铁线："+starLine);
for (Station station : result.getPassStations()) {
if(!converLine.equals(station.getLine())){
System.out.print("换乘地铁线："+station.getLine()+" ");
converLine = station.getLine();
converLine = station.getLine();
}
System.out.print(station.getName() + " > ");
}
}
运行结果
