hello-algo/codes/c/chapter_graph/graph_adjacency_list.c
Yudong Jin d26e811e10
Several bug fixes and improvements. (#887)
* fix the bugs of C code.

* Add a header figure.

* Improve the definition of tree node height.
2023-10-25 22:59:25 +08:00

264 lines
7.6 KiB
C

/**
* File: graph_adjacency_list.c
* Created Time: 2023-07-07
* Author: NI-SW (947743645@qq.com)
*/
#include "../utils/common.h"
typedef struct Vertex Vertex;
typedef struct Node Node;
typedef struct LinkedList LinkedList;
void freeVertex(Vertex *);
void freeLinklist(LinkedList *);
LinkedList *newLinklist(Vertex *);
/* 链表节点 */
struct Node {
// 链表节点内包含顶点类和下一个节点地址
Vertex *val;
Node *next;
};
/* 链表节点构造函数 */
Node *newNode() {
Node *n = (Node *)malloc(sizeof(Node));
n->next = 0;
n->val = 0;
return n;
}
/* 顶点节点类 */
struct Vertex {
// 节点值
int val;
// 与其它节点相连接的边的链表
LinkedList *list;
// 索引位,标记该顶点在顶点列表中的索引
unsigned int pos;
};
/* 顶点节点构造函数 */
Vertex *newVertex(int val) {
Vertex *vet = (Vertex *)malloc(sizeof(Vertex));
// 为新节点赋值并建立该节点的链表
vet->val = val;
vet->list = newLinklist(vet);
return vet;
}
/* 顶点内存释放函数 */
void freeVertex(Vertex *val) {
// 释放该顶点和该顶点的链表的内存
freeLinklist(val->list);
free(val);
}
/* 链表 */
struct LinkedList {
Node *head;
Node *tail;
};
/* 链表头插法 */
void pushFront(LinkedList *list, Vertex *val) {
Node *temp = newNode();
temp->val = val;
temp->next = list->head->next;
list->head->next = temp;
if (list->tail == list->head) {
list->tail = temp;
}
}
/* 链表尾插法 */
void pushBack(LinkedList *list, Vertex *val) {
Node *temp = newNode();
temp->val = val;
temp->next = 0;
list->tail->next = temp;
list->tail = temp;
}
/* 根据顶点地址与该顶点连接的删除边 */
void removeLink(LinkedList *list, Vertex *val) {
Node *temp = list->head->next;
Node *front = list->head;
while (temp != 0) {
if (temp->val == val) {
front->next = temp->next;
if (list->tail == temp) {
list->tail = front;
}
free(temp);
return;
}
front = temp;
temp = temp->next;
}
if (temp->next == 0) {
printf("vertex not found!\n");
}
}
/* 根据顶点地址删除顶点 */
void removeItem(LinkedList *list, Vertex *val) {
Node *temp = list->head->next;
Node *front = list->head;
while (temp != 0) {
if (temp->val == val) {
front->next = temp->next;
if (list->tail == temp) {
list->tail = front;
}
freeVertex(val);
free(temp);
return;
}
front = temp;
temp = temp->next;
}
if (temp->next == 0) {
printf("vertex not found!\n");
}
}
/* 释放链表内存 */
void freeLinklist(LinkedList *list) {
Node *temp = list->head->next;
while (temp != 0) {
free(list->head);
list->head = temp;
temp = temp->next;
}
free(list->head);
list->head = 0;
free(list);
}
/* 链表构造函数 */
LinkedList *newLinklist(Vertex *val) {
LinkedList *newLinklist = (LinkedList *)malloc(sizeof(LinkedList));
newLinklist->head = newNode();
newLinklist->head->val = val;
newLinklist->tail = newLinklist->head;
newLinklist->head->next = 0;
return newLinklist;
}
/* 基于邻接链表实现的无向图类结构 */
typedef struct {
Vertex **vertices; // 邻接表
unsigned int size; // 顶点数量
unsigned int capacity; // 顶点容量
} GraphAdjList;
/* 添加边 */
void addEdge(GraphAdjList *graph, int i, int j) {
// 越界检查
if (i < 0 || j < 0 || i == j || i >= graph->size || j >= graph->size) {
printf("Out of range in %s:%d\n", __FILE__, __LINE__);
return;
}
// 查找欲添加边的顶点 vet1 - vet2
Vertex *vet1 = graph->vertices[i];
Vertex *vet2 = graph->vertices[j];
// 连接顶点 vet1 - vet2
pushBack(vet1->list, vet2);
pushBack(vet2->list, vet1);
}
/* 删除边 */
void removeEdge(GraphAdjList *graph, int i, int j) {
// 越界检查
if (i < 0 || j < 0 || i == j || i >= graph->size || j >= graph->size) {
printf("Out of range in %s:%d\n", __FILE__, __LINE__);
return;
}
// 查找欲删除边的顶点 vet1 - vet2
Vertex *vet1 = graph->vertices[i];
Vertex *vet2 = graph->vertices[j];
// 移除待删除边 vet1 - vet2
removeLink(vet1->list, vet2);
removeLink(vet2->list, vet1);
}
/* 添加顶点 */
void addVertex(GraphAdjList *graph, int val) {
// 若大小超过容量,则扩容
if (graph->size >= graph->capacity) {
Vertex **tempList = (Vertex **)malloc(sizeof(Vertex *) * 2 * graph->capacity);
memcpy(tempList, graph->vertices, sizeof(Vertex *) * graph->size);
free(graph->vertices); // 释放原邻接表内存
graph->vertices = tempList; // 指向新邻接表
graph->capacity = graph->capacity * 2; // 容量扩大至2倍
}
// 申请新顶点内存并将新顶点地址存入顶点列表
Vertex *newV = newVertex(val); // 建立新顶点
newV->pos = graph->size; // 为新顶点标记下标
newV->list = newLinklist(newV); // 为新顶点建立链表
graph->vertices[graph->size] = newV; // 将新顶点加入邻接表
graph->size++;
}
/* 删除顶点 */
void removeVertex(GraphAdjList *graph, unsigned int index) {
// 越界检查
if (index < 0 || index >= graph->size) {
printf("Out of range in %s:%d\n", __FILE__, __LINE__);
exit(1);
}
Vertex *vet = graph->vertices[index]; // 查找待删节点
if (vet == 0) { // 若不存在该节点,则返回
printf("index is:%d\n", index);
printf("Out of range in %s:%d\n", __FILE__, __LINE__);
return;
}
// 遍历待删除顶点的链表,将所有与待删除结点有关的边删除
Node *temp = vet->list->head->next;
while (temp != 0) {
removeLink(temp->val->list, vet); // 删除与该顶点有关的边
temp = temp->next;
}
// 将顶点前移
for (int i = index; i < graph->size - 1; i++) {
graph->vertices[i] = graph->vertices[i + 1]; // 顶点前移
graph->vertices[i]->pos--; // 所有前移的顶点索引值减 1
}
graph->vertices[graph->size - 1] = 0;
graph->size--;
// 释放内存
freeVertex(vet);
}
/* 打印顶点与邻接矩阵 */
void printGraph(GraphAdjList *graph) {
printf("邻接表 =\n");
for (int i = 0; i < graph->size; i++) {
Node *n = graph->vertices[i]->list->head->next;
printf("%d: [", graph->vertices[i]->val);
while (n != 0) {
if (n->next != 0) {
printf("%d, ", n->val->val);
} else {
printf("%d", n->val->val);
}
n = n->next;
}
printf("]\n");
}
}
/* 构造函数 */
GraphAdjList *newGraphAdjList(unsigned int verticesCapacity) {
// 申请内存
GraphAdjList *newGraph = (GraphAdjList *)malloc(sizeof(GraphAdjList));
// 建立顶点表并分配内存
newGraph->vertices = (Vertex **)malloc(sizeof(Vertex *) * verticesCapacity); // 为顶点列表分配内存
memset(newGraph->vertices, 0, sizeof(Vertex *) * verticesCapacity); // 顶点列表置 0
newGraph->size = 0; // 初始化顶点数量
newGraph->capacity = verticesCapacity; // 初始化顶点容量
// 返回图指针
return newGraph;
}