1 import java.util.Scanner;  2   3 public class Station {  4   5     static String strA = "A1 A2 A3 A4 A5 A6 A7 A8 A9 T1 A10 A11 A12 A13 T2 A14 A15 A16 A17 A18";  6     static String strB = "B1 B2 B3 B4 B5 T1 B6 B7 B8 B9 B10 T2 B11 B12 B13 B14 B15";  7       8     static String[] SA = strA.split(" ");  9     static String[] SB = strB.split(" "); 10      11     static int LENSA = SA.length; 12     static int LENSB = SB.length; 13      14     public static void main(String[] args) { 15          16         int step = 0; 17         System.out.println("请输入\"始发站\"（空格）\"终到站\"(例如：A1 B4（回车结束）)："); 18         Scanner sc = new Scanner(System.in); 19         String[] strArray = sc.nextLine().split(" "); 20          21         String x = strArray[0].toUpperCase(); 22         String y = strArray[1].toUpperCase(); 23          24         System.out.println("go:"+x); 25         System.out.println("to:"+y); 26          27         sc.close(); 28          29         step = getMinStep(x, y) + 1;//实际最小步数应该为getMinStep(x, y)，此处按题示要求，所以结果加1 30         System.out.println("经过的最少车站数："+step); 31     } 32  33     private static int getMinStep(String x, String y) { 34          35         if((‘A‘ != x.charAt(0))&&(‘A‘ != y.charAt(0))) 36         { 37             //在地铁B线路上，不用换乘，已经包含T1到T2 38             return stepBtoB(x, y); 39         } 40         else if((‘B‘ != x.charAt(0))&&(‘B‘ != y.charAt(0))) 41         { 42             //在地铁A线路上 43             return stepAtoA(x, y); 44         } 45         else 46         { 47             //A到B，或者B到A 48             return stepT1orT2(x, y); 49         } 50     } 51  52     //从T1或者T2站换乘，s1到s2的最短距离 53     private static int stepT1orT2(String s1, String s2) { 54         int lenXtoT1 = steptoT1(s1); 55         int lenXtoT2 = steptoT2(s1); 56         int lenYtoT1 = steptoT1(s2); 57         int lenYtoT2 = steptoT2(s2); 58          59         int lineT1 = lenXtoT1 + lenYtoT1; 60         int lineT2 = lenXtoT2 + lenYtoT2; 61          62         return min(lineT1, lineT2); 63     } 64  65     //到T1的最短距离 66     private static int steptoT1(String s) { 67          68         if(‘A‘ == s.charAt(0)) 69         { 70             //找到s站在SA的下标 71             int i = getIndexofSA(s); 72              73             //找到"T1"站在SA的下标 74             int j = getIndexofSA("T1"); 75              76             //找到"T2"站在SA的下标 77             int k = getIndexofSA("T2"); 78              79             //不换乘，s到T1最短路程 80             int line1 = min(mod(i, j), LENSA-mod(i, j)); 81             //不换乘，s到T2最短路程 82             int line2 = min(mod(i, k), LENSA-mod(i, k)); 83              84             return min(line1, line2+stepBtoB("T1", "T2")); 85         } 86         else 87         { 88             return stepBtoB(s, "T1"); 89         } 90     } 91  92     //到T2的最短距离 93     private static int steptoT2(String s) { 94  95         if(‘A‘ == s.charAt(0)) 96         { 97             //找到s站在SA的下标 98             int i = getIndexofSA(s); 99             100             //找到"T1"站在SA的下标101             int j = getIndexofSA("T1");102             103             //找到"T2"站在SA的下标104             int k = getIndexofSA("T2");105             106             //不换乘，s到T1最短路程107             int line1 = min(mod(i, j), LENSA-mod(i, j));108             //不换乘，s到T2最短路程109             int line2 = min(mod(i, k), LENSA-mod(i, k));110             111             return min(line1+stepBtoB("T1", "T2"), line2);112         }113         else114         {115             return stepBtoB(s, "T2");116         }117     }118 119     //A到A，有可能会从T1或者T2中转120     private static int stepAtoA(String s1, String s2) {121         if((‘B‘ == s1.charAt(0))||(‘B‘ == s2.charAt(0)))122         {123             System.out.println("输入不是A线路上的站点，请检查！");124             return -1;125         }126         127         //找到s1站在SA的下标128         int i = getIndexofSA(s1);129         130         //找到s2站在SA的下标131         int j = getIndexofSA(s2);132         133         //不换乘，s1到s2的最短距离134         int line1 = min(mod(i, j), LENSA-mod(i, j));135         136         //从T1或者T2站换乘，s1到s2的最短距离137         int line2 = stepT1orT2(s1, s2);138         139         return min(line1, line2);140     }141 142     //B到B143     private static int stepBtoB(String s1, String s2) {144         if((‘A‘ == s1.charAt(0))||(‘A‘ == s2.charAt(0)))145         {146             System.out.println("输入不是B线路上的站点，请检查！");147             return -1;148         }149         150         //找到s1站在SB的下标151         int i = getIndexofSB(s1);152         153         //找到s2站在SB的下标154         int j = getIndexofSB(s2);155         156         //取两数之模157         return mod(i, j);158     }159     160     private static int min(int a, int b)161     {162         return a<b?a:b;163     }164 165     private static int getIndexofSA(String str)166     {167         for(int index = 0; index < LENSA; index++)168         {169             if(str.equals(SA[index]))170             {171                 return index;172             }173         }174         175         return -1;176     }177 178     private static int getIndexofSB(String str)179     {180         for(int index = 0; index < LENSB; index++)181         {182             if(str.equals(SB[index]))183             {184                 return index;185             }186         }187         188         return -1;189     }190     191     private static int mod(int a, int b)192     {193         if(a < b)194         {195             return b-a;196         }197         else198         {199             return a-b;200         }201     }202 }