用c语言实现：输入一组顶点，建立有向图的邻接表。并举例出有效输入

以下是示例代码，使用邻接表表示有向图：

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

#define MAX_VERTEX_NUM 100 // 最大顶点数

// 邻接表中的边结构体
typedef struct EdgeNode {
    int adjvex; // 邻接顶点编号
    struct EdgeNode *next; // 指向下一个邻接点的指针
} EdgeNode;

// 邻接表中的顶点结构体
typedef struct VertexNode {
    int vertex; // 顶点编号
    EdgeNode *firstedge; // 指向第一个邻接点的指针
} VertexNode;

// 有向图的邻接表结构体
typedef struct {
    VertexNode vertexs[MAX_VERTEX_NUM]; // 存储顶点的数组
    int vexnum, edgenum; // 顶点数和边数
} GraphAdjList;

// 初始化有向图的邻接表
void InitGraph(GraphAdjList *G, int vexnum) {
    G->vexnum = vexnum;
    G->edgenum = 0;
    // 初始化每个顶点
    for (int i = 0; i < vexnum; i++) {
        G->vertexs[i].vertex = i;
        G->vertexs[i].firstedge = NULL;
    }
}

// 添加一条边到有向图的邻接表
void AddEdge(GraphAdjList *G, int tail, int head) {
    // 创建一个邻接点
    EdgeNode *p = (EdgeNode *)malloc(sizeof(EdgeNode));
    p->adjvex = head;
    p->next = G->vertexs[tail].firstedge;
    G->vertexs[tail].firstedge = p;
    G->edgenum++;
}

// 输出有向图的邻接表
void PrintGraph(GraphAdjList G) {
    printf("Vertex number: %d, Edge number: %d\n", G.vexnum, G.edgenum);
    for (int i = 0; i < G.vexnum; i++) {
        printf("Vertex %d: ", G.vertexs[i].vertex);
        EdgeNode *p = G.vertexs[i].firstedge;
        while (p) {
            printf("%d ", p->adjvex);
            p = p->next;
        }
        printf("\n");
    }
}

int main() {
    int n;
    printf("Input number of vertices: ");
    scanf("%d", &n);
    GraphAdjList G;
    InitGraph(&G, n);
    printf("Input edges (input -1 -1 to end):\n");
    int tail, head;
    scanf("%d%d", &tail, &head);
    while (tail != -1 && head != -1) {
        if (tail < 0 || tail >= n || head < 0 || head >= n) {
            printf("Invalid input!\n");
        } else {
            AddEdge(&G, tail, head);
        }
        scanf("%d%d", &tail, &head);
    }
    PrintGraph(G);
    return 0;
}

输入示例：

Input number of vertices: 4
Input edges (input -1 -1 to end):
0 1
1 2
2 3
3 0
-1 -1

输出示例：

Vertex number: 4, Edge number: 4
Vertex 0: 1 
Vertex 1: 2 
Vertex 2: 3 
Vertex 3: 0