【转】邻接表的DFS、BFS、两结点的全部简单路径

晚上看视频的时候一不小心把浏览器关了，所以丢失了原文链接...

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#define MAX_VERTEX_NUM 20
#define OVERFLOW 0
#define OK 1
#define TRUE 1  
#define FALSE 0 
typedef  int   Status  ;
typedef  char VertexType;
typedef  int  QElemType;
typedef struct ArcNode
{
     int adjvex;                            //邻接点域，存储该邻点顶点对应的下标
     struct ArcNode *nextarc;             //邻节点
     int weight;                        //权值
}ArcNode;
/*邻接表结构*/
typedef struct VNode
{
     VertexType data;                   //顶点对应的值
     ArcNode  *firstarc;            //边表头指针指向邻顶点
}VNode,AdjList[MAX_VERTEX_NUM];
 
typedef struct
{
     AdjList  vertices;  
     int vexnum,arcnum;                //顶点数,边数
}ALGraph;
 
/*队列结构*/
 
typedef struct QNode     
{  
    QElemType data;  
    struct QNode *next;  
}QNode,*QueuePtr;   
 
typedef struct {
    int    data[MAX_VERTEX_NUM];
    int    front, rear;
}Queue;
 
//队列顺序表的相关操作
//初始化
void InitQueue(Queue *Q)
{
    Q->front = Q->rear = 0;
}
 
//入队
void EnQueue(Queue *Q, int e)
{
    if ((Q->rear+1)%MAX_VERTEX_NUM == Q->front)
        return ;
    Q->data[Q->rear] = e;
    Q->rear = (Q->rear+1)%MAX_VERTEX_NUM;
}
 
//判空
int QueueEmpty(Queue *Q)
{
    if (Q->front == Q->rear)
        return 1;
    else
        return 0;
}
 
//出队
void DeQueue(Queue *Q, int *e)
{
    if (Q->front == Q->rear)
        return ;
    
    *e = Q->data[Q->front];
    Q->front = (Q->front+1)%MAX_VERTEX_NUM;
}
 
 
void CreateALGraph(ALGraph *G)    //构建图
{
     ArcNode *p;
     int i,j,k;
     printf("输入顶点与边的数目:
");
     scanf("%d%d",&G->vexnum,&G->arcnum);
     getchar();
     printf("输入顶点值:
");
    for(i=1;i<=G->vexnum;i++)
    {
          scanf("%c",&G->vertices[i].data);
          getchar();
          G->vertices[i].firstarc=NULL;
    }
    //建立边表
    printf("输入邻接表对应的下标:（从1开始）
");
    for(k=1;k<=G->arcnum;k++)
    {
          scanf("%d%d",&i,&j);   //边对应的两个顶点下标并将俩顶点联系起来
          p = (ArcNode *)malloc(sizeof(ArcNode));
          p->adjvex = j;
          p->nextarc = G->vertices[i].firstarc;
          G->vertices[i].firstarc = p;
          /*有向图只要上部分即可*/ 
          p  =  (ArcNode*)malloc(sizeof(ArcNode));
          p->adjvex = i;
          p->nextarc = G->vertices[j].firstarc;
          G->vertices[j].firstarc = p;
    }
}
 
int visited[MAX_VERTEX_NUM];        //记录是否被访问
/*邻接表的深度遍历*/ 
void DFS(ALGraph G,int i)
{
     int j;
     ArcNode *p;
     visited[i]=1;     //将要访问的顶点置为1
     printf("%c ",G.vertices[i].data); //输出各顶点
     for(p = G.vertices[i].firstarc;p!=NULL;p=p->nextarc)
     {
            j = p->adjvex;
          if(visited[j]==0) //深度探索
            DFS(G,j);
     }
}
 
void Is_connected(ALGraph G)
{
     int i;
     int count = 0;
     for(i=1;i<=G.vexnum;i++)
          visited[i]=0;      //初始化0，未被访问
     for(i=1;i<=G.vexnum;i++)
     {
          if(!visited[i])
          {
               printf("
");
               DFS(G,i);
               count++;  //记录连通图个数(>1)则整体是个非连通图
          }
     }
     printf("
连通图个数为:%d
",count);
}
 
/*邻接表的广度遍历*/
void BFSTraverse(ALGraph g)
{
    ArcNode *p;
       Queue Q;   
       InitQueue(&Q);  
    for(int i = 1; i <= g.vexnum; i++)
    {
        visited[i] = 0;
    }  
    for(int j = 1; j<=g.vexnum; j++)
    {
        if(!visited[j])
        {
            printf("%c ", g.vertices[j].data);   //打印顶点，也可以其他操作
            visited[j] = 1;
            EnQueue(&Q,j);
            while(!QueueEmpty(&Q))
            {
                int m;
                DeQueue(&Q,&m);                        //访问点出队列 
                p = g.vertices[m].firstarc;     //找到当前顶点边表链表头指针
                while(p)                 
                {
                    if(!visited[p->adjvex])
                    {
                        printf("%c ", g.vertices[p->adjvex].data);
                        visited[p->adjvex] = 1;
                        EnQueue(&Q, p->adjvex);
                    }
                        p = p->nextarc;
                }
            }
        }
    }
}
 
int flag = 0;      //标志探寻点置0
int top = 0;
char path[MAX_VERTEX_NUM];
 
/*连通图的简单路径（类dfs) */
void pathdfs(ALGraph G,int i,int j)
{
    ArcNode *p;
    int s,w;
    visited[i]=1;           //将顶点i加入当前路径
    path[++top] = G.vertices[i].data;
    if(!flag && path[top]==G.vertices[j].data)
        flag = 1;   //存在顶点i到顶点j的路径
    if(flag)       //找到
    {
    //输出当前路径上所有顶点
        printf("
");
    for(s=1;s<=top;s++)
        printf("%c	",path[s]);
        flag = 0;
    }
    else
    for(p=G.vertices[i].firstarc;p;p=p->nextarc)
    {
        w = p->adjvex;
        if(!visited[w])
        pathdfs(G,w,j);
    }
        visited[i]=0;         //每当顶点i回溯时，把visited[i]置为0，下次可通过顶点i寻找其他可能到达j的路径
        top--;               //删除顶点i
 
}
 
int main()
{
        ALGraph G;
        CreateALGraph(&G);
        printf("-------------------
");
        printf("简单路径为:");
        pathdfs(G,1,3);
        printf("
连通图的深度遍历为:");
        Is_connected(G);
        printf("
连通图的广度遍历为:");
        BFSTraverse(G);
        return 0;
}

/*
样例图:
       2
      /  
    /      
   1--------3
   |        |
   |        |
   5--------4

样例输入：
5 6
1 2 3 4 5
1 2
1 3
1 5
2 3
3 4
4 5
*/