用栈实现拓扑排序

#include<stdio.h>#include<stdlib.h>#define MAXVEX 100      //最大顶点数typedef char VertexType;     //顶点typedef int EdgeType;   //权值#define UNVISITED -1    //标记未访问#define VISITED 1   //标记未访问#define OK 1#define ERROR 0typedef int Status;typedef struct{    int from;   //边的始点    int to; //边的终点    EdgeType weight;    //权重}Edge;  //边的结构typedef struct EdgeNode{    int adjvex; //该顶点对应的下标    EdgeType weight;    //权重    struct EdgeNode * next;}EdgeNode;typedef struct  //顶点结构{    int in; //记录入度    VertexType data;    EdgeNode * firstedge;}VertexNode,AdjList[MAXVEX];typedef struct{    AdjList adjList;    int numVertexes;    int numEdges;    int Mark[MAXVEX];   //标记是否被访问过}GraphAdjList;  //图结构//初始化邻接表void InitGraphAdjList(GraphAdjList * G,int numVer,int numEd)    //传入顶点数和边数{    G->numVertexes=numVer;    G->numEdges=numEd;    for(int i=0;i<G->numVertexes;i++)    {        G->Mark[i]=UNVISITED;        G->adjList[i].in=0;        G->adjList[i].firstedge=NULL;   //将边表置空表    }}//创建一条边(有向图)void Creat_Edge(GraphAdjList * G,int from,int to,int weight){    EdgeNode * temp= G->adjList[from].firstedge;    if(temp==NULL)    {        EdgeNode * NewEdgeNode=(EdgeNode *)malloc(sizeof(EdgeNode));        NewEdgeNode->adjvex=to;        NewEdgeNode->weight=weight;        NewEdgeNode->next=NULL;        G->adjList[from].firstedge=NewEdgeNode;        G->adjList[to].in++;    }    else    {        while(temp->next!=NULL)        {            temp=temp->next;        }        EdgeNode * NewEdgeNode=(EdgeNode *)malloc(sizeof(EdgeNode));        NewEdgeNode->adjvex=to;        NewEdgeNode->weight=weight;        NewEdgeNode->next=NULL;        temp->next=NewEdgeNode;        G->adjList[to].in++;    }}/*建立图的邻接表结构（有向图）*/void GreateALGraph(GraphAdjList * G){    int i,j,k,w;    printf("请输入%d个元素：\n",G->numVertexes);    for(i=0;i<G->numVertexes;i++)   /*读入顶点信息，建立顶点表*/    {        scanf(" %c",&G->adjList[i].data);   /*输入顶点信息*/        G->adjList[i].firstedge=NULL;   /*将边表置空表*/    }    for(k=0;k<G->numEdges;k++)  /*建立边表*/    {        printf("输入边(Vi,Vj)上的顶点序号和权重：\n");        scanf("%d%d%d",&i,&j,&w);   /*输入(Vi,Vj)上的顶点序号*/        Creat_Edge(G,i,j,w);    }}Edge FirstEdge(GraphAdjList * G,int oneVertex){    Edge firstEdge;    firstEdge.from=oneVertex;    EdgeNode * temp=G->adjList[oneVertex].firstedge;    if(temp!=NULL)    {        firstEdge.to=temp->adjvex;        firstEdge.weight=temp->weight;    }    else    {        firstEdge.to=-1;        firstEdge.weight=-1;    }    return firstEdge;}//返回oneEdge的终点int ToVertex(Edge oneEdge){    return oneEdge.to;}//返回与perEdge相同顶点的下一条边Edge NextEdge(GraphAdjList * G,Edge perEdge){    Edge myEdge;    myEdge.from=perEdge.from;    EdgeNode * temp=G->adjList[perEdge.from].firstedge;    while(temp!=NULL && temp->adjvex<=perEdge.to)    {        temp=temp->next;    }    if(temp!=NULL)    {        myEdge.to=temp->adjvex;        myEdge.weight=temp->weight;    }    else    {        myEdge.to=-1;        myEdge.weight=-1;    }    return myEdge;}//判断是否为边bool IsEdge(Edge oneEdge){    if(oneEdge.to==-1)    {        return false;    }    else    {        return true;    }}//拓扑排序算法Status ToPologicalSort(GraphAdjList * G){    Edge e;    int i,k,gettop;    int top=0;      //用于栈指针下标    int count=0;    //统计输出的顶点个数    int * stack;    //建栈存储顶点个数    stack=(int *)malloc(G->numVertexes * sizeof(int));    for(i=0;i<G->numVertexes;i++)    {        if(G->adjList[i].in==0) //将入度为0的顶点元素的下标入栈        {            stack[++top]=i;        }    }    while(top!=0)   //栈不为空    {        gettop=stack[top--];        printf("%c ",G->adjList[gettop].data);        count++;    //记录输出的顶点个数        for(e=FirstEdge(G,gettop);IsEdge(e);e=NextEdge(G,e))        {            k=e.to; //记录当前邻接点            if(!(--G->adjList[k].in))   //将k的顶点邻接点的入度减1，查看入度是否为0;如果为0,则入栈            {                stack[++top]=k;            }        }    }        if(count<G->numVertexes)    //输出的顶点个数小于顶点个数，说明有环        {            printf("此图有环！\n");            return ERROR;        }        else        {            return OK;        }}int main(){    GraphAdjList G;    int numVer,numEd;    int start;    int choose;    printf("请输入顶点元素个数和边数：\n");    scanf("%d%d",&numVer,&numEd);    InitGraphAdjList(&G,numVer,numEd);    GreateALGraph(&G);    ToPologicalSort(&G);    printf("\n");    return 0;}