邻接表有向图的介绍

// 邻接表中表对应的链表的顶点
typedef struct _ENode
{
    int ivex;                   // 该边所指向的顶点的位置
    struct _ENode *next_edge;   // 指向下一条弧的指针
}ENode, *PENode;

// 邻接表中表的顶点
typedef struct _VNode
{
    char data;              // 顶点信息
    ENode *first_edge;      // 指向第一条依附该顶点的弧
}VNode;

// 邻接表
typedef struct _LGraph
{
    int vexnum;             // 图的顶点的数目
    int edgnum;             // 图的边的数目
    VNode vexs[MAX];
}LGraph;

#include<stdlib.h>
#include<stdio.h>
#include<string.h>
#include<malloc.h>
#define MAX 100

typedef struct ENode
{
    int ivex;
    struct ENode *next_edge;
}ENode;

typedef struct VNode
{
    char data;
    struct ENode *first_edge;
}VNode;

typedef struct LGraph
{
    int vexnum;
    int edgnum;
    VNode vexs[MAX];
}LGraph;

int get_position(LGraph g,char ch)
{
    int i;
    for(i=0;i<g.vexnum;i++)
        if(ch==g.vexs[i].data)
            return i;
    return -1;
}

LGraph* create_graph()
{
    char vexs[]= {‘A‘,‘B‘,‘C‘,‘D‘,‘E‘,‘F‘,‘G‘};
    char edges[][2]= {{‘A‘,‘C‘},{‘A‘,‘D‘},{‘A‘,‘F‘},{‘B‘,‘C‘},{‘C‘,‘D‘},{‘E‘,‘G‘},{‘F‘,‘G‘}};
    int vlen=sizeof(vexs)/sizeof(vexs[0]);
    int  elen=sizeof(edges)/sizeof(edges[0]);
    int i,p1,p2;
    ENode *node2;
    LGraph *pG;
    if((pG=(LGraph*)malloc(sizeof(LGraph)))==NULL)
        return NULL;
    memset(pG,0,sizeof(pG));
    pG->edgnum=elen;
    pG->vexnum=vlen;
    for(i=0;i<pG->vexnum;i++)
    {
        pG->vexs[i].data=vexs[i];
        pG->vexs[i].first_edge=NULL;
    }
    for(i=0;i<pG->edgnum;i++)
    {
        p1=get_position(*pG,edges[i][0]);
        p2=get_position(*pG,edges[i][1]);
        node2=(ENode*)malloc(sizeof(ENode));
        node2->ivex=p2;
        node2->next_edge=NULL;
        if(pG->vexs[p1].first_edge==NULL)
            pG->vexs[p1].first_edge=node2;
        else
        {
            ENode *tmp=pG->vexs[p1].first_edge;
            while(tmp->next_edge)
            {
                tmp=tmp->next_edge;
            }
            tmp->next_edge=node2;
        }
    }
    return pG;
}

void print_graph(LGraph G)
{
    int i;
    printf("List Graph:\n");
    ENode *node=NULL;
    for(i=0;i<G.vexnum;i++)
    {
        printf("%d(%c): ", i, G.vexs[i].data);
        node=G.vexs[i].first_edge;
        while(node)
        {
            printf("%d(%c) ", node->ivex, G.vexs[node->ivex].data);
            node=node->next_edge;
        }
        printf("\n");
    }
}

int main()
{
    LGraph *pG;
    pG=create_graph();
    print_graph(*pG);
}