北京地铁乘坐路线查询

来源:互联网 发布:兔小将是什么 知乎 编辑:程序博客网 时间:2024/03/29 07:21

【问题描述】

编写一个程序实现北京地铁最短乘坐(站)线路查询,输入为起始站名和目的站名,输出为从起始站到目的站的最短乘坐站换乘线路。注:1. 要求采用Dijkstra算法实现;2)本题在实际测试时对数据文件进行了调整,使得输入的两站间只有一条最短路径。

【输入形式】

文件bgstations.txt为数据文件(可从课程网站中课程信息处下载),包含了北京地铁的线路及车站信息。其格式如下:

<地铁线路总条数>

<线路1> <线路1站数>

<站名1> <换乘状态>

<站名2> <换乘状态>

...

<线路2> <线路2站数>

<站名1> <换乘状态>

<站名2> <换乘状态>

...

说明:文件第一行为地铁总线路数;第二行第一个数为某条地铁线线号(如,1为1号线),第二个数为该条地铁线的总站数(如1号线共有23站),两数之间由一个空格分隔;第三行两个数据分别为地铁站名及换乘状态(0为非换乘站,1为换乘站),两数据间由一个空格分隔;以下同,依次为该线地铁其它站信息。在一条线路信息之后是下条地铁线路信息,格式相同。若某条地铁线为环线,则首站与末站信息相同(如北京地铁2号线,首站信息“西直门 1” ,末站信息为“西直门 1”)。例如本题提供的bgstations.txt文件(可从课程网站中课程信息处下载)内容如下:

12

1 23

苹果园 0

古城 0

八角游乐园 0

八宝山 0

玉泉路 0

五棵松 0

万寿路 0

公主坟 1

军事博物馆 1

木樨地 0

南礼士路 0

复兴门 1

西单 1

...

2 19

西直门 1

积水潭 0

鼓楼大街 1

...

西直门 1

...

该文件表明当前北京地铁共有12条线路(不含郊区线路),接着为每条线路信息。

打开当前目录下文件bgstations.txt,读入地铁线路信息,并从标准输入中读入起始站和目的站名(均为字符串,各占一行)。


【输出形式】

输出从起始站到目的站的乘坐信息,要求乘坐站数最少。换乘信息格式如下:

SSN-n1(m1)-S1-n2(m2)-...-ESN

其中:SSN和ESN分别为起始站名和目的站名;n为乘坐的地铁线路号,m为乘坐站数。
【样例输入】

西土城

北京西站

【样例输出】

西土城-10(1)-知春路-13(2)-西直门-4(2)-国家图书馆-9(4)-北京西站

【样例说明】

打开文件bgstations.txt,读入地铁线路信息,并从标准输入中读入查询起始站名为“西土城”,目的站名为“北京西站”。程序运行结果两站间最少乘坐站数的乘坐方式为“西土城站乘坐10号线1站至知春路站换乘13号线乘坐2站至西直门站换乘4号线乘坐2站至国家图书馆站换乘9号线乘坐4站至北京西站”。

#include <stdio.h>#include <stdlib.h>#include <string.h>#define MAXSTRLEN 41#define INF 0x3f3f3f3f#define MAXSTATNUM 500typedef struct _Edge{int adjseq;int weight;int lineseq;struct _Edge *next;} Edge;typedef struct _Station{char name[MAXSTRLEN];int trans;int lineseq;int statseq;Edge *link;} Station;typedef struct _Line{int size;int seq;int isloop;struct _Station *list;} Line;typedef struct _Railway{int size;struct _Station list[MAXSTATNUM];} Railway;void insert_Edge(Station *head, int end, int lineseq){Edge *rear = head->link;Edge *newEdge = (Edge *)malloc(sizeof(Edge));if (newEdge == NULL) {printf("allocation failure");exit(1);}newEdge->weight = 1;newEdge->lineseq = lineseq;newEdge->adjseq = end;newEdge->next = NULL;if (rear == NULL){head->link = newEdge;}else{while (rear->next != NULL) rear = rear->next; // reach the rearrear->next = newEdge;// add the new Edge at the rear}}void input_Station(Railway *railway, Line line, int seq_inline, int seq_inrail){// input a station in a processed line to a railway system, and in this case seq_inrail == railway->sizestrcpy(railway->list[seq_inrail].name, line.list[seq_inline].name);railway->list[seq_inrail].trans = line.list[seq_inline].trans;railway->list[seq_inrail].lineseq = line.seq;railway->list[seq_inrail].statseq = seq_inrail;railway->list[seq_inrail].link = NULL;railway->size++;if (seq_inline == 0){// the first stationif (line.isloop){// the line is a loop, with the same station as start and endinsert_Edge(&(railway->list[seq_inrail]), line.list[1].statseq, line.seq);insert_Edge(&(railway->list[seq_inrail]), line.list[line.size - 2].statseq, line.seq);}else{// the start station in a non-loop has no previous stationinsert_Edge(&(railway->list[seq_inrail]), line.list[1].statseq, line.seq);}}else if (seq_inline == line.size - 1 - line.isloop){// the last stationif (line.isloop){// the line is a loop, with the same station as start and endinsert_Edge(&(railway->list[seq_inrail]), line.list[0].statseq, line.seq);insert_Edge(&(railway->list[seq_inrail]), line.list[line.size - 3].statseq, line.seq);}else{// the last station in a non-loop has no following stationinsert_Edge(&(railway->list[seq_inrail]), line.list[line.size - 2].statseq, line.seq);}}else{insert_Edge(&(railway->list[seq_inrail]), line.list[seq_inline + 1].statseq, line.seq);insert_Edge(&(railway->list[seq_inrail]), line.list[seq_inline - 1].statseq, line.seq);}}void update_Station(Railway *railway, Line line, int seq_inline, int seq_inrail){// update a station's edges in a railway systemif (seq_inline == 0){// the first stationif (line.isloop){// the line is a loop, with the same station as start and endinsert_Edge(&(railway->list[seq_inrail]), line.list[1].statseq, line.seq);insert_Edge(&(railway->list[seq_inrail]), line.list[line.size - 2].statseq, line.seq);}else{// the start station in a non-loop has no previous stationinsert_Edge(&(railway->list[seq_inrail]), line.list[1].statseq, line.seq);}}else if (seq_inline == line.size - 1 - line.isloop){// the last stationif (line.isloop){// the line is a loop, with the same station as start and endinsert_Edge(&(railway->list[seq_inrail]), line.list[0].statseq, line.seq);insert_Edge(&(railway->list[seq_inrail]), line.list[line.size - 3].statseq, line.seq);}else{// the last station in a non-loop has no following stationinsert_Edge(&(railway->list[seq_inrail]), line.list[line.size - 2].statseq, line.seq);}}else{insert_Edge(&(railway->list[seq_inrail]), line.list[seq_inline + 1].statseq, line.seq);insert_Edge(&(railway->list[seq_inrail]), line.list[seq_inline - 1].statseq, line.seq);}}int in_Rail(Railway railway, char name[]){// find the station and return its sequence number in railsystemsint iter_rail;for (iter_rail = 0; iter_rail < railway.size; iter_rail++){if (strcmp(railway.list[iter_rail].name, name) == 0)return iter_rail;}return -1; // not found}void input_Line(Railway *railway, Line line){// inputting a processed line into a railway systemint seq_inline, seq_inrail;if (railway->size == 0) // empty system{// initialize a railway systemfor (seq_inline = 0; seq_inline < line.size; seq_inline++){// in an empty railway system, the inline seq equals the inrail seqrailway->list[seq_inline].link = NULL;input_Station(railway, line, seq_inline, seq_inline);}}else{int seq_fromsize = railway->size;for (seq_inline = 0; seq_inline < line.size - line.isloop; seq_inline++){seq_inrail = in_Rail(*railway, line.list[seq_inline].name);if (seq_inrail != -1){// this station already exists in the railway systemupdate_Station(railway, line, seq_inline, seq_inrail);}else{// this is a new stationinput_Station(railway, line, seq_inline, seq_fromsize);seq_fromsize++;}}}}void process_Line(Railway *railway, Line *line){// pre-process the statseq of the stations in a line (for the inputting of stations)int seq_inline, seq_inrail;if (railway->list == NULL){// empty railway systemfor (seq_inline = 0; seq_inline < line->size; seq_inline++)line->list[seq_inline].statseq = seq_inline;}else{int seq_fromsize = railway->size;for (seq_inline = 0; seq_inline < line->size; seq_inline++){seq_inrail = in_Rail(*railway, line->list[seq_inline].name);if (seq_inrail != -1){// this station already exists in the railway systemline->list[seq_inline].statseq = seq_inrail;}else{// new stationline->list[seq_inline].statseq = seq_fromsize;seq_fromsize++;}}}}void Dijkstra(Railway *railway, char startname[], char destname[], int path[]){int start = in_Rail(*railway,startname);int dest = in_Rail(*railway, destname);int *dist = (int *)malloc(railway->size*sizeof(int)); // dist[] stores the minimum distance from start to the indexed station// 0 means this station has been enclosedmemset(dist, INF, railway->size*sizeof(int));dist[start] = 0;Edge *link = railway->list[start].link;while (link != NULL){dist[link->adjseq] = link->weight;path[link->adjseq] = start;link = link->next;}while (dist[dest] == INF){int min = INF, minstat = dest, iter;for (iter = 0; iter < railway->size; iter++){if (dist[iter] != 0 && dist[iter] < min){// not enclosed, and find the minimummin = dist[iter];minstat = iter;}}link = railway->list[minstat].link;if (link == NULL) exit(1);while (link != NULL){if (dist[minstat] + link->weight < dist[link->adjseq]){dist[link->adjseq] = dist[minstat] + link->weight;path[link->adjseq] = minstat;}link = link->next;}dist[minstat] = 0;}free(dist);/* just for debuggingwhile (dest != start){printf("%s<-",railway->list[dest].name);dest = path[dest];}printf("%s\n", railway->list[start].name);*/}int get_Lineseq(Railway railway, int stat1, int stat2){Edge *link = railway.list[stat1].link;while (link != NULL){if (link->adjseq == stat2)return link->lineseq;link = link->next;}return -1; // not connected}void depict_Path(Railway *railway, int start, int dest, int path[]){int *track = (int *)malloc(railway->size*sizeof(int));memset(track, INF, railway->size*sizeof(int));int iter = 0;while (dest != start){track[iter++] = dest;dest = path[dest];}track[iter] = start;int i = 0, j = iter;while (i < j){// reverse track[]int tmp;tmp = track[j];track[j] = track[i];track[i] = tmp;i++, j--;}/*for (i = 0; i <= iter; i++)printf("%s %d -", railway->list[track[i]].name, railway->list[track[i]].lineseq);*/int currstats = 1;printf("%s-",railway->list[track[0]].name);for (i = 1; i < iter; i++){if (   get_Lineseq(*railway, railway->list[track[i - 1]].statseq, railway->list[track[i]].statseq)!= get_Lineseq(*railway, railway->list[track[i + 1]].statseq, railway->list[track[i]].statseq)){// the previous station and the next one is not on the same line: transfering printf("%d(%d)-%s-", get_Lineseq(*railway, railway->list[track[i - 1]].statseq, railway->list[track[i]].statseq), currstats, railway->list[track[i]].name);currstats = 1;}else{currstats++;}}printf("%d(%d)-%s\n", get_Lineseq(*railway, railway->list[track[i - 1]].statseq, railway->list[track[i]].statseq), currstats, railway->list[track[iter]].name);}int main(){FILE *fin;fin = fopen("bgstations.txt","r");if (fin == NULL) exit(1);int linenum, lineseq, statnum, trans;int i, j;char statname[MAXSTRLEN];Railway *beijing = (Railway *)malloc(sizeof(Railway));beijing->size = 0;Line *newline = (Line *)malloc(sizeof(Line));fscanf(fin,"%d\n",&linenum);for (i = 1; i <= linenum; i++){fscanf(fin, "%d %d\n",&lineseq, &statnum);newline->seq = lineseq;newline->size = statnum; newline->isloop = 0;newline->list = (Station *)malloc(statnum*sizeof(Station));for (j = 0; j < statnum; j++){fscanf(fin, "%s %d\n", statname, &trans);newline->list[j].lineseq = i;strcpy(newline->list[j].name,statname);newline->list[j].trans = trans;}if (strcmp(newline->list[0].name, statname) == 0)newline->isloop = 1;process_Line(beijing, newline);input_Line(beijing, *newline);free(newline->list);fscanf(fin, "\n");}char startname[MAXSTRLEN], destname[MAXSTRLEN];scanf("%s",startname);scanf("%s",destname);int *path = (int *)malloc(beijing->size*sizeof(int));Dijkstra(beijing, startname, destname, path);depict_Path(beijing, in_Rail(*beijing, startname), in_Rail(*beijing, destname), path);/* just for debuggingfor (i = 0; i < beijing->size; i++){printf("%s %d %d\n", beijing->list[i].name, beijing->list[i].statseq, beijing->list[i].trans);Edge *curr = beijing->list[i].link;while (curr != NULL){printf("%s %d %d\n", beijing->list[curr->adjseq].name, curr->adjseq, beijing->list[curr->adjseq].trans);curr = curr->next;}}*/free(newline);free(path);fclose(fin);return 0;}


0 0
原创粉丝点击