创建无向图的邻接表c语言

以下是创建无向图的邻接表的C语言代码示例：

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

struct Node {
    int vertex;
    struct Node* next;
};

struct Graph {
    int numVertices;
    struct Node** adjLists;
};

struct Node* createNode(int v) {
    struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));
    newNode->vertex = v;
    newNode->next = NULL;
    return newNode;
}

struct Graph* createGraph(int vertices) {
    struct Graph* graph = (struct Graph*)malloc(sizeof(struct Graph));
    graph->numVertices = vertices;

    graph->adjLists = (struct Node**)malloc(vertices * sizeof(struct Node*));

    int i;
    for (i = 0; i < vertices; i++)
        graph->adjLists[i] = NULL;

    return graph;
}

void addEdge(struct Graph* graph, int src, int dest) {
    // Add edge from src to dest
    struct Node* newNode = createNode(dest);
    newNode->next = graph->adjLists[src];
    graph->adjLists[src] = newNode;

    // Add edge from dest to src
    newNode = createNode(src);
    newNode->next = graph->adjLists[dest];
    graph->adjLists[dest] = newNode;
}

void printGraph(struct Graph* graph) {
    int v;
    for (v = 0; v < graph->numVertices; v++) {
        struct Node* temp = graph->adjLists[v];
        printf("\n Adjacency list of vertex %d\n head ", v);
        while (temp) {
            printf("-> %d", temp->vertex);
            temp = temp->next;
        }
        printf("\n");
    }
}

int main() {
    struct Graph* graph = createGraph(4);
    addEdge(graph, 0, 1);
    addEdge(graph, 0, 2);
    addEdge(graph, 1, 2);
    addEdge(graph, 2, 3);

    printGraph(graph);

    return 0;
}

这个例子中，我们创建了一个无向图的邻接表，它包含4个顶点。我们使用`createGraph`函数创建一个名为`graph`的指向图的结构体的指针。然后，我们使用`addEdge`函数添加顶点之间的边。最后，我们使用`printGraph`函数打印邻接表。

这个例子中的无向图如下所示：

     1
   /   \
  0     2
   \   /
     3

打印出来的邻接表如下所示：

 Adjacency list of vertex 0
 head -> 2-> 1

 Adjacency list of vertex 1
 head -> 2-> 0

 Adjacency list of vertex 2
 head -> 3-> 1-> 0

 Adjacency list of vertex 3
 head -> 2