用C语言完成基于邻接表表示法实现图的广度优先遍历

以下是使用邻接表表示法实现图的广度优先遍历的 C 语言代码：

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

#define MAX_NODES 1000
#define QUEUE_SIZE 1000

typedef struct node {
    int vertex;
    struct node* next;
} node_t;

node_t* graph[MAX_NODES];
int visited[MAX_NODES];
int queue[QUEUE_SIZE];
int front = -1, rear = -1;

void add_edge(int src, int dest) {
    node_t* new_node = malloc(sizeof(node_t));
    new_node->vertex = dest;
    new_node->next = graph[src];
    graph[src] = new_node;
}

void bfs(int start) {
    int i, vertex;
    node_t* temp;

    visited[start] = 1;
    queue[++rear] = start;

    while (front != rear) {
        vertex = queue[++front];
        printf("%d ", vertex);

        for (temp = graph[vertex]; temp != NULL; temp = temp->next) {
            i = temp->vertex;
            if (!visited[i]) {
                visited[i] = 1;
                queue[++rear] = i;
            }
        }
    }
}

int main() {
    int n, e, i, src, dest;

    printf("Enter the number of nodes: ");
    scanf("%d", &n);

    printf("Enter the number of edges: ");
    scanf("%d", &e);

    for (i = 0; i < n; i++) {
        graph[i] = NULL;
        visited[i] = 0;
    }

    printf("Enter the edges:\n");
    for (i = 0; i < e; i++) {
        scanf("%d %d", &src, &dest);
        add_edge(src, dest);
        add_edge(dest, src); // 如果是无向图，还要加上 dest 到 src 的边
    }

    printf("Enter the starting node: ");
    scanf("%d", &src);

    printf("BFS traversal starting from node %d: ", src);
    bfs(src);

    return 0;
}

这个程序使用了一个邻接表来表示图，输入时需要手动输入。第一行输入节点数和边数，接下来输入每条边连接的两个节点。最后输入起始节点，程序会输出从这个节点开始的广度优先遍历结果。