用邻接表表示图

#pragma warning(disable:4996)
#include<malloc.h>
#include<stdio.h>
#define MaxVertexNum 100 //最大顶点数设为100
typedef int Vertex; //用顶点下标表示顶点，为整型
typedef int WeightType;
typedef char DataType; //顶点存储的数据类型设为字符型

//边的定义
typedef struct ENode* PtrToENode;
struct ENode {
Vertex V1, V2; //有向边<V1,V2>
WeightType Weight; //权重
};
typedef PtrToENode Edge;

//邻接点的定义
typedef struct AdjVNode* PtrToAdjVNode;
struct AdjVNode {
Vertex AdjV; //邻接点下标
WeightType Weight; //边权重
PtrToAdjVNode Next; //指向下一个邻接点的指针
};

//顶点表头结点的定义
typedef struct Vnode {
PtrToAdjVNode FirstEdge; //边表头指针
DataType Data; //存顶点的数据
}AdjList[MaxVertexNum]; //AdjList是邻接表类型

//图结点的定义
typedef struct GNode* PtrToGNode;
struct GNode {
int Nv; //顶点数
int Ne; //边数
AdjList G; //邻接表
};
typedef PtrToGNode LGraph; //以邻接矩阵存储的图类型

LGraph CreateGraph(int VertexNum) {
//初始化一个有Vertex个顶点但没有边的图
Vertex V, W;
LGraph Graph;
Graph = (LGraph)malloc(sizeof(struct GNode));//建立图
Graph->Nv = VertexNum;
Graph->Ne = 0;
//初始化邻接表表头
//这里默认编号从0开始
for (V = 0; V < Graph->Nv; V++) {
Graph->G[V].FirstEdge = NULL;
}
return Graph;
}

void InsertEdge(LGraph Graph, Edge E) {
PtrToAdjVNode NewNode;
//插入边
//为V2建立新的邻接点
NewNode = (PtrToAdjVNode)malloc(sizeof(struct AdjVNode));
NewNode->AdjV = E->V2;
NewNode->Weight = E->Weight;
//将V2插入V1的表头
NewNode->Next = Graph->G[E->V1].FirstEdge;
Graph->G[E->V1].FirstEdge = NewNode;

//若是无向图，还要插入边<V2,V1>
/* 为V1建立新的邻接点 */
NewNode = (PtrToAdjVNode)malloc(sizeof(struct AdjVNode));
NewNode->AdjV = E->V1;
NewNode->Weight = E->Weight;
/* 将V1插入V2的表头 */
NewNode->Next = Graph->G[E->V2].FirstEdge;
Graph->G[E->V2].FirstEdge = NewNode;
}

LGraph BuildGraph() {
LGraph Graph;
Edge E;
Vertex V;
int Nv, i;

scanf("%d", &Nv); //读入顶点个数
Graph = CreateGraph(Nv); //初始化有Nv个顶点但没有边的图

scanf("%d", &(Graph->Ne)); //读入边数
if (Graph->Ne != 0) { //如果有边
E = (Edge)malloc(sizeof(struct ENode)); //建立边结点
//读入边，格式为“起点，终点，权重”，插入邻接矩阵
for (i = 0; i < Graph->Ne; i++) {
scanf("%d %d %d ", &E->V1, &E->V2, &E->Weight);
//如果权重不是整型，weight的读入格式要改
InsertEdge(Graph, E);
}
}
//如果顶点有数据，则读入顶点
for (V = 0; V < Graph->Nv; V++) {
scanf("%c", &(Graph->G[V].Data));
}
return Graph;
}