（1）graph.h
/*****************************************************************************
* *
* -------------------------------- graph.h ------------------------------- *
* *
*****************************************************************************/
#ifndef GRAPH_H
#define GRAPH_H
#include <stdlib.h>
#include "list.h"
#include "set.h"
/*****************************************************************************
* *
* Define a structure for adjacency lists. *
* *
*****************************************************************************/
typedef struct AdjList_ { // 保存vertex指向的頂點值的領接結點
void *vertex;
Set adjacent;
} AdjList;
/*****************************************************************************
* *
* Define a structure for graphs. *
* *
*****************************************************************************/
typedef struct Graph_ {
int vcount; // 點的數量
int ecount; // 邊的數量
int (*match)(const void *key1, const void *key2);
void (*destroy)(void *data);
List adjlists; // 鏈表，存的是每個結構體的地址
} Graph;
/*****************************************************************************
* *
* Define colors for vertices in graphs. *
* *
*****************************************************************************/
typedef enum VertexColor_ {white, gray, black} VertexColor;
/*****************************************************************************
* *
* --------------------------- Public Interface --------------------------- *
* *
*****************************************************************************/
void graph_init(Graph *graph, int (*match)(const void *key1, const void
*key2), void (*destroy)(void *data));
void graph_destroy(Graph *graph);
int graph_ins_vertex(Graph *graph, const void *data);
int graph_ins_edge(Graph *graph, const void *data1, const void *data2);
int graph_rem_vertex(Graph *graph, void **data);
int graph_rem_edge(Graph *graph, void *data1, void **data2);
int graph_adjlist(const Graph *graph, const void *data, AdjList **adjlist);
int graph_is_adjacent(const Graph *graph, const void *data1, const void
*data2);
#define graph_adjlists(graph) ((graph)->adjlists)
#define graph_vcount(graph) ((graph)->vcount)
#define graph_ecount(graph) ((graph)->ecount)
#endif
（2）graph.c
/*****************************************************************************
* *
* -------------------------------- graph.c ------------------------------- *
* *
*****************************************************************************/
#include <stdlib.h>
#include <string.h>
#include "graph.h"
#include "list.h"
#include "set.h"
/*****************************************************************************
* *
* ------------------------------ graph_init ------------------------------ *
* *
*****************************************************************************/
void graph_init(Graph *graph, int (*match)(const void *key1, const void
*key2), void (*destroy)(void *data)) {
/*****************************************************************************
* *
* Initialize the graph. *
* *
*****************************************************************************/
graph->vcount = 0;
graph->ecount = 0;
graph->match = match;
graph->destroy = destroy;
/*****************************************************************************
* *
* Initialize the list of adjacency-list structures. *
* *
*****************************************************************************/
list_init(&graph->adjlists, NULL);
return;
}
/*****************************************************************************
* *
* ----------------------------- graph_destroy ---------------------------- *
* *
*****************************************************************************/
void graph_destroy(Graph *graph) {
AdjList *adjlist;
/*****************************************************************************
* *
* Remove each adjacency-list structure and destroy its adjacency list. *
* *
*****************************************************************************/
while (list_size(&graph->adjlists) > 0) {
if (list_rem_next(&graph->adjlists, NULL, (void **)&adjlist) == 0) {
set_destroy(&adjlist->adjacent);
if (graph->destroy != NULL)
graph->destroy(adjlist->vertex);
free(adjlist);
}
}
/*****************************************************************************
* *
* Destroy the list of adjacency-list structures, which is now empty. *
* *
*****************************************************************************/
list_destroy(&graph->adjlists);
/*****************************************************************************
* *
* No operations are allowed now, but clear the structure as a precaution. *
* *
*****************************************************************************/
memset(graph, 0, sizeof(Graph));
return;
}
/*****************************************************************************
* *
* --------------------------- graph_ins_vertex --------------------------- *
* *
*****************************************************************************/
int graph_ins_vertex(Graph *graph, const void *data) {
ListElmt *element;
AdjList *adjlist;
int retval;
/*****************************************************************************
* *
* Do not allow the insertion of duplicate vertices. *
* *
*****************************************************************************/
for (element = list_head(&graph->adjlists); element != NULL; element =
list_next(element)) {
// 判斷插入的結點值是否重複
if (graph->match(data, ((AdjList *)list_data(element))->vertex))
return 1;
}
/*****************************************************************************
* *
* Insert the vertex. *
* *
*****************************************************************************/
// 爲新的結構體申請內存
if ((adjlist = (AdjList *)malloc(sizeof(AdjList))) == NULL)
return -1;
adjlist->vertex = (void *)data;
set_init(&adjlist->adjacent, graph->match, graph->destroy);
// 在鏈表中插入新的結構體指針(AdjList)
if ((retval = list_ins_next(&graph->adjlists, list_tail(&graph->adjlists),
adjlist)) != 0) {
return retval;
}
/*****************************************************************************
* *
* Adjust the vertex count to account for the inserted vertex. *
* *
*****************************************************************************/
graph->vcount++; // 頂點個數加一
return 0;
}
/*****************************************************************************
* *
* ---------------------------- graph_ins_edge ---------------------------- *
* *
*****************************************************************************/
int graph_ins_edge(Graph *graph, const void *data1, const void *data2) {
ListElmt *element;
int retval;
/*****************************************************************************
* *
* Do not allow insertion of an edge without both its vertices in the graph. *
* *
*****************************************************************************/
// 新邊中的端點必須都在圖中
for (element = list_head(&graph->adjlists); element != NULL; element =
list_next(element)) {
if (graph->match(data2, ((AdjList *)list_data(element))->vertex))
break;
}
if (element == NULL)
return -1;
for (element = list_head(&graph->adjlists); element != NULL; element =
list_next(element)) {
if (graph->match(data1, ((AdjList *)list_data(element))->vertex))
break;
}
if (element == NULL)
return -1;
/*****************************************************************************
* *
* Insert the second vertex into the adjacency list of the first vertex. *
* *
*****************************************************************************/
// 插入第一個頂點的領接鏈表中
if ((retval = set_insert(&((AdjList *)list_data(element))->adjacent, data2))
!= 0) {
return retval;
}
/*****************************************************************************
* *
* Adjust the edge count to account for the inserted edge. *
* *
*****************************************************************************/
graph->ecount++; // 邊的數目加一
return 0;
}
/*****************************************************************************
* *
* --------------------------- graph_rem_vertex --------------------------- *
* *
*****************************************************************************/
int graph_rem_vertex(Graph *graph, void **data) {
ListElmt *element,
*temp,
*prev;
AdjList *adjlist;
int found;
/*****************************************************************************
* *
* Traverse each adjacency list and the vertices it contains. *
* *
*****************************************************************************/
prev = NULL;
found = 0;
for (element = list_head(&graph->adjlists); element != NULL; element =
list_next(element)) {
/**************************************************************************
* *
* Do not allow removal of the vertex if it is in an adjacency list. *
* *
**************************************************************************/
if (set_is_member(&((AdjList *)list_data(element))->adjacent, *data))
return -1;
/**************************************************************************
* *
* Keep a pointer to the vertex to be removed. *
* *
**************************************************************************/
if (graph->match(*data, ((AdjList *)list_data(element))->vertex)) {
temp = element;
found = 1;
}
/**************************************************************************
* *
* Keep a pointer to the vertex before the vertex to be removed. *
* *
**************************************************************************/
if (!found)
prev = element; // 尋找需要移除頂點在鏈表中的前一個位置的頂點。方便鏈表刪除操作
}
/*****************************************************************************
* *
* Return if the vertex was not found. *
* *
*****************************************************************************/
if (!found)
return -1;
/*****************************************************************************
* *
* Do not allow removal of the vertex if its adjacency list is not empty. *
* *
*****************************************************************************/
if (set_size(&((AdjList *)list_data(temp))->adjacent) > 0)
return -1;
/*****************************************************************************
* *
* Remove the vertex. *
* *
*****************************************************************************/
if (list_rem_next(&graph->adjlists, prev, (void **)&adjlist) != 0)
return -1;
/*****************************************************************************
* *
* Free the storage allocated by the abstract data type. *
* *
*****************************************************************************/
*data = adjlist->vertex;
free(adjlist);
/*****************************************************************************
* *
* Adjust the vertex count to account for the removed vertex. *
* *
*****************************************************************************/
graph->vcount--;
return 0;
}
/*****************************************************************************
* *
* ---------------------------- graph_rem_edge ---------------------------- *
* *
*****************************************************************************/
int graph_rem_edge(Graph *graph, void *data1, void **data2) {
ListElmt *element;
/*****************************************************************************
* *
* Locate the adjacency list for the first vertex. *
* *
*****************************************************************************/
for (element = list_head(&graph->adjlists); element != NULL; element =
list_next(element)) {
if (graph->match(data1, ((AdjList *)list_data(element))->vertex))
break;
}
if (element == NULL)
return -1;
/*****************************************************************************
* *
* Remove the second vertex from the adjacency list of the first vertex. *
* *
*****************************************************************************/
if (set_remove(&((AdjList *)list_data(element))->adjacent, data2) != 0)
return -1;
/*****************************************************************************
* *
* Adjust the edge count to account for the removed edge. *
* *
*****************************************************************************/
graph->ecount--;
return 0;
}
/*****************************************************************************
* *
* ----------------------------- graph_adjlist ---------------------------- *
* *
*****************************************************************************/
int graph_adjlist(const Graph *graph, const void *data, AdjList **adjlist) {
ListElmt *element,
*prev;
/*****************************************************************************
* *
* Locate the adjacency list for the vertex. *
* *
*****************************************************************************/
prev = NULL;
for (element = list_head(&graph->adjlists); element != NULL; element =
list_next(element)) {
if (graph->match(data, ((AdjList *)list_data(element))->vertex))
break;
prev = element;
}
/*****************************************************************************
* *
* Return if the vertex was not found. *
* *
*****************************************************************************/
if (element == NULL)
return -1;
/*****************************************************************************
* *
* Pass back the adjacency list for the vertex. *
* *
*****************************************************************************/
*adjlist = list_data(element);
return 0;
}
/*****************************************************************************
* *
* --------------------------- graph_is_adjacent -------------------------- *
* *
*****************************************************************************/
int graph_is_adjacent(const Graph *graph, const void *data1, const void
*data2) {
ListElmt *element,
*prev;
/*****************************************************************************
* *
* Locate the adjacency list of the first vertex. *
* *
*****************************************************************************/
prev = NULL;
for (element = list_head(&graph->adjlists); element != NULL; element =
list_next(element)) {
if (graph->match(data1, ((AdjList *)list_data(element))->vertex))
break;
prev = element;
}
/*****************************************************************************
* *
* Return if the first vertex was not found. *
* *
*****************************************************************************/
if (element == NULL)
return 0;
/*****************************************************************************
* *
* Return whether the second vertex is in the adjacency list of the first. *
* *
*****************************************************************************/
return set_is_member(&((AdjList *)list_data(element))->adjacent, data2);
}