用邻接表储存无向图C语言

以下是使用邻接表储存无向图的C语言代码示例：

#include <stdio.h>
#include <stdlib.h>

// 邻接表节点结构体
typedef struct node {
    int dest;               // 目标顶点编号
    struct node *next;      // 下一个邻接节点指针
} Node;

// 邻接表结构体
typedef struct adj_list {
    Node *head;             // 邻接表头指针
} AdjList;

// 图结构体
typedef struct graph {
    int num_vertices;       // 顶点数量
    AdjList *adj_lists;     // 邻接表指针数组
} Graph;

// 创建邻接表节点
Node* create_node(int dest) {
    Node* node = (Node*) malloc(sizeof(Node));
    node->dest = dest;
    node->next = NULL;
    return node;
}

// 创建图
Graph* create_graph(int num_vertices) {
    Graph* graph = (Graph*) malloc(sizeof(Graph));
    graph->num_vertices = num_vertices;
    graph->adj_lists = (AdjList*) malloc(num_vertices * sizeof(AdjList));
    for (int i = 0; i < num_vertices; i++) {
        graph->adj_lists[i].head = NULL;
    }
    return graph;
}

// 添加边
void add_edge(Graph* graph, int src, int dest) {
    // 添加 src -> dest
    Node* node = create_node(dest);
    node->next = graph->adj_lists[src].head;
    graph->adj_lists[src].head = node;

    // 添加 dest -> src
    node = create_node(src);
    node->next = graph->adj_lists[dest].head;
    graph->adj_lists[dest].head = node;
}

// 打印邻接表
void print_graph(Graph* graph) {
    for (int i = 0; i < graph->num_vertices; i++) {
        Node* node = graph->adj_lists[i].head;
        printf("Vertex %d: ", i);
        while (node != NULL) {
            printf("%d -> ", node->dest);
            node = node->next;
        }
        printf("NULL\n");
    }
}

int main() {
    // 创建一个包含4个顶点的无向图
    Graph* graph = create_graph(4);
    add_edge(graph, 0, 1);
    add_edge(graph, 0, 2);
    add_edge(graph, 1, 2);
    add_edge(graph, 2, 3);

    // 打印邻接表
    print_graph(graph);

    return 0;
}

这段代码会创建一个包含4个顶点的无向图，然后添加4条边，并打印邻接表。你可以根据需要修改顶点数量和边的数量。