PTA路径判断

#include <stdio.h>
#define MVNum 100                 //最大顶点数 
typedef struct{ 
  char vexs[MVNum];           //存放顶点的一维数组 
  int arcs[MVNum][MVNum];     //邻接矩阵 
  int vexnum,arcnum;          //图的当前顶点数和弧数 
}MGraph; 

int visited[MVNum];
void CreatMGraph(MGraph *G);/* 创建图 */
void panduan(MGraph *G);    //路径判断
void DFS(MGraph *G,int i);    //深度搜索
 
int main()
{
    MGraph G;
    CreatMGraph(&G);
    panduan(&G);
    return 0;
}
void CreatMGraph(MGraph *G)
{
    int i, j, k;
    scanf("%d %d",&G->vexnum,&G->arcnum);
    getchar();
    for(i=0;i<G->vexnum;i++){
        G->vexs[i] = i;
    }
    for(i=0;i<G->vexnum;i++){
        for(j=0;j<G->vexnum;j++)
            G->arcs[i][j] = 0;
    }     
    for(k=0;k<G->arcnum;k++){  
       scanf("%d %d",&i,&j);     
           G->arcs[i][j] = 1;
           G->arcs[j][i] = 1;    
    }
}

void panduan(MGraph *G){
    int i, j, k;
    scanf("%d %d", &i, &j);
    for (k=0; k<G->vexnum; k++){
        visited[k] = 0;
    }
    DFS(G, i);
    if (visited[j] == 1){
        printf("There is a path between %d and %d.", i, j);
    }
    else {
        printf("There is no path between %d and %d.", i, j);
    }
    
}

void DFS(MGraph *G,int i){    
    int j;    
    visited[i] = 1;   //被访问的标记         
    for(j=0; j<G->vexnum; j++)    
    {        
        if(G->arcs[i][j]==1 && !visited[j])   //边(i,j)存在且j顶点未被访问，递归             
            DFS(G, j);    
    } 
}