地铁换乘

墨蓝 2022-07-12 12:13 196阅读 0赞

package 搜索;  
  
  
import java.io.BufferedReader;  
import java.io.FileReader;  
import java.util.ArrayList;  
import java.util.HashMap;  
import java.util.HashSet;  
import java.util.Map;  
import java.util.Scanner;  
  
  
/\*\*  
\* 利用深度查询 A-B 第一条线路有  
\*  
\* @author Administrator  
\*  
\*/  
  
  
public class 地铁换乘 \{  
static class Line \{  
// 线路名  
public String lineName;  
// 站点集合  
public ArrayList<String> site = new ArrayList<String>();  
// 相交的节点  
public HashSet<Line> acrossLine = new HashSet<Line>();  
  
  
@Override  
public String toString() \{  
return "Line \[lineName=" + lineName + ", site=" + site.toString()  
\+ ", acrossLine=" + acrossLine.toString() + "\]";  
\}  
\}  
  
  
static ArrayList<Line> liArr = new ArrayList<Line>();// 所有线路  
static Map<String, Integer> priceArr = new HashMap<String, Integer>();// 所有路线价格  
static ArrayList<String> resultSet = new ArrayList<String>();// 结果集  
static ArrayList<String> a = new ArrayList<String>();// 用来过滤重复结果  
// 1:读取线路  
static \{  
try \{  
// 读取线路  
readLine();  
// 读取价格  
readPrice();  
\} catch (Exception e) \{  
\}  
  
  
\}  
  
  
public static void main(String\[\] args) \{  
@SuppressWarnings("resource")  
Scanner sc = new Scanner(System.in);  
System.out.println("请输入起始站和终点:");  
String str = sc.nextLine();  
// 2：查询起点到终点所有线路  
findLine(str);  
// 3:最优价格以及路线  
String result = getLinePrice();  
// 4:输出  
System.out.println(result);  
\}  
  
  
/\*\*  
\* 3:最优价格  
\*  
\* @return  
\*/  
private static String getLinePrice() \{  
int\[\] priceAr = new int\[resultSet.size()\];  
for (int i = 0; i < resultSet.size(); i++) \{  
String\[\] st = resultSet.get(i).split("-");// 路线数组  
int price = 0;// 花费  
String str = "";// 路线  
boolean flag = false;// 上一条线路是否是联合票  
for (int k = 1; k < st.length; k++) \{  
// 不包含联合票,解决了单程问题,巧妙利用之前添加的"-"  
if (!priceArr.containsKey(st\[k - 1\] + st\[k\])) \{  
price += priceArr.get(st\[k\]);  
str = str + "-" + st\[k\];  
flag = false;  
continue;  
\}  
/\*  
\* 包含联合票价 1：前一个线路包含联合票价 2：前一个线路不包含联合票价  
\*/  
if (flag) \{  
int p1 = priceArr.get(st\[k - 2\] + st\[k - 1\])  
\+ priceArr.get(st\[k\]);  
int p2 = priceArr.get(st\[k - 1\] + st\[k\])  
\+ priceArr.get(st\[k - 2\]);  
if (p1 <= p2) \{  
price += priceArr.get(st\[k\]);  
str = str + "-" + st\[k\];  
\} else \{  
price = price - priceArr.get(st\[k - 2\] + st\[k - 1\])  
\+ p2;  
str = str.replace("(" + st\[k - 2\] + "," + st\[k - 1\]  
\+ ")", st\[k - 2\] + "-(" + st\[k - 1\] + ","  
\+ st\[k\] + ")");  
\}  
\} else \{  
price -= priceArr.get(st\[k - 1\]);  
price += priceArr.get(st\[k - 1\] + st\[k\]);  
str = str.replace(st\[k - 1\], "(" + st\[k - 1\] + "," + st\[k\]  
\+ ")");  
\}  
  
  
flag = true;  
  
  
\}  
// 更新票价以及路线结果集  
resultSet.set(i, str);  
priceAr\[i\] = price;  
\}  
  
  
int minIndex = 0;  
for (int i = 1; i < priceAr.length; i++) \{  
if (priceAr\[i\] < priceAr\[minIndex\]) \{  
minIndex = i;  
\}  
\}  
return resultSet.get(minIndex) + " " + priceAr\[minIndex\] + "";  
  
  
\}  
  
  
/\*\*  
\* 查询起点到终点所有线路  
\*  
\* @param str  
\*/  
private static void findLine(String str) \{  
String\[\] split = str.split(",");  
String start = split\[0\];// 起点  
String end = split\[1\];// 终点  
ArrayList<Line> startLine = new ArrayList<>();  
ArrayList<Line> endLine = new ArrayList<>();  
/\*  
\* 1:包含起点和终点分别添加入对应的集合中  
\*/  
for (Line l : liArr) \{  
if (l.site.contains(start))  
startLine.add(l);  
if (l.site.contains(end))  
endLine.add(l);  
\}  
/\*  
\* 2:判断，<0：说明无线路。异常  
\*/  
if (startLine.size() == 0 || endLine.size() == 0) \{  
new Exception("无效输入");  
\}  
  
  
/\*  
\* 3:获取起点到终点的所有方案  
\*/  
for (Line l1 : startLine)  
for (Line l2 : endLine) \{  
a.add(l1.lineName);  
// 迭代l1-l2所有结果  
findResult(resultSet.size(), l1, l2, " -" + l1.lineName);  
\}  
  
  
\}  
  
  
/\*\*  
\* 查找乘车线路  
\*  
\* @param rn  
\* :乘车方案个数，作用，用来判断是否到了终点  
\* @param l1  
\* ：起点  
\* @param l2  
\* :终点  
\* @param result  
\* :方案  
\*/  
private static void findResult(int rn, Line l1, Line l2, String result) \{  
/\*  
\* 情况1：单程线路  
\* 情况2:2-多程线路  
\*/  
if (l1 == l2) \{  
resultSet.add(result);  
return;  
\}  
/\*  
\* 情况2：交叉线路  
\*/  
for (Line acrossLine : l1.acrossLine) \{  
// 线路已经被找过  
if (a.contains(acrossLine.lineName)) \{  
continue;  
\}  
// 找到终点时  
if (acrossLine == l2) \{  
a.add(acrossLine.lineName);  
resultSet.add(result + "-" + acrossLine.lineName);  
\}  
\}  
/\*  
\* 情况3：多×线路  
\*/  
if (resultSet.size() > rn)// 说明rn在前面改变过，间接说明已经找到了终点  
return;  
for (Line acrossLine : l1.acrossLine) \{  
// 线路已经被找过  
if (a.contains(acrossLine.lineName)) \{  
continue;  
\}  
a.add(acrossLine.lineName);  
findResult(resultSet.size(), acrossLine, l2, result + "-"  
\+ acrossLine.lineName);  
\}  
  
  
\}  
  
  
/\*\*  
\* 读取价格  
\*  
\* @throws Exception  
\*/  
private static void readPrice() throws Exception \{  
BufferedReader br = new BufferedReader(new FileReader("src/price.txt"));  
String p;  
while ((p = br.readLine()) != null) \{  
String\[\] split = p.split(" ");  
if (split\[0\].contains(",")) \{// 说明是交叉线路  
String\[\] split2 = split\[0\].split(",");  
priceArr.put(split2\[0\] + split2\[1\], Integer.parseInt(split\[1\]));  
priceArr.put(split2\[1\] + split2\[0\], Integer.parseInt(split\[1\]));  
\} else \{// 单程车票  
priceArr.put(split\[0\], Integer.parseInt(split\[1\]));  
\}  
\}  
br.close();  
\}  
  
  
/\*\*  
\* 读取线路  
\*  
\* @throws Exception  
\*/  
private static void readLine() throws Exception \{  
BufferedReader br = new BufferedReader(new FileReader(  
"src/stations.txt"));  
ArrayList<String> temp = new ArrayList<String>();  
String p;  
Line l = null;  
while ((p = br.readLine()) != null) \{  
if (p.contains("线")) \{// 说明开始  
l = new Line();  
l.lineName = p;  
liArr.add(l);  
\} else if (p.equals(""))  
continue;  
else \{  
l.site.add(p);  
\}  
// 说明有交叉路线  
if (temp.contains(p)) \{  
findCrossL(p, l);  
\} else \{  
temp.add(p);  
\}  
  
  
\}  
br.close();  
  
  
\}  
  
  
/\*\*  
\* 添加交叉路线  
\*  
\* @param p  
\* @param l  
\*/  
private static void findCrossL(String p, Line l) \{  
for (int i = 0; i < liArr.size() - 1; i++) \{// 减1，是因为不包含当前线路  
Line line = liArr.get(i);  
// 包含当前站点，说明互为交叉  
if (line.site.contains(p)) \{  
line.acrossLine.add(l);  
l.acrossLine.add(line);  
\}  
\}  
  
  
\}  
\}