#include <stdio.h> #include <stdlib.h> #define INFINITY 32768 #define MaxVexNum 20 typedef int ElemType; typedef enum {DG, DN, UDG, UDN} GraphKind; typedef struct { ElemType vexs[1000]; int arcs[1000][1000]; int vexnum, arcnum; } AMGraph; int locate(AMGraph G, char v) { int k; for (k = 0; k < G.vexnum; k++) { if (G.vexs[k] == v) { return k; } } return -1; } void CreatMGraph(AMGraph *G) { int i, j, k; int v1, v2; scanf("%d%d", &G->vexnum, &G->arcnum); getchar(); for (i = 0; i < G->vexnum; i++) { for (j = 0; j < G->vexnum; j++) { G->arcs[i][j] = 0; } } for(i=0;i<G->vexnum;i++) { G->vexs[i]=i+1; } for (k = 0; k < G->arcnum; k++) { scanf("%d%d", &v1, &v2); getchar(); i = locate(*G, v1); j = locate(*G, v2); G->arcs[i][j] = 1; G->arcs[j][i] = 1; } } int visited[MaxVexNum]; void DepthFirstSearch(AMGraph g, int v0) { visited[v0] = 1; for (int vj = 0; vj < g.vexnum; vj++) { if (!visited[vj] && g.arcs[v0][vj] == 1) { DepthFirstSearch(g, vj); } } } void TraverseGraph(AMGraph g,int v0) { for (int vi = 0; vi < g.vexnum; vi++) { visited[vi] = 0; } DepthFirstSearch(g, v0); } int main() { int v0,v1; AMGraph G; CreatMGraph(&G); scanf("%d%d",&v0,&v1); TraverseGraph(G,v0); if(visited[v1]==1) printf("yes"); else printf("no"); return 0; }修改

代码中的问题是数组越界访问，`visited`数组的大小应该与顶点数`G.vexnum`相同，而不是固定的`MaxVexNum`。因此需要将代码中的`visited`数组定义修改为：

int visited[1000];

同时，函数`DepthFirstSearch`和`TraverseGraph`中的参数`g`需要改为指针类型，以便在函数中修改`visited`数组。修改后的代码如下：

#include <stdio.h> 
#include <stdlib.h>  

#define INFINITY 32768 
#define MaxVexNum 20  

typedef int ElemType;  
typedef enum {DG, DN, UDG, UDN} GraphKind;  

typedef struct {     
    ElemType vexs[1000];     
    int arcs[1000][1000];     
    int vexnum, arcnum; 
} AMGraph;  

int locate(AMGraph G, char v) {     
    int k;     
    for (k = 0; k < G.vexnum; k++) {         
        if (G.vexs[k] == v) {             
            return k;         
        }     
    }     
    return -1; 
}  

void CreatMGraph(AMGraph *G) {     
    int i, j, k;     
    int v1, v2;     
    scanf("%d%d", &G->vexnum, &G->arcnum);     
    getchar();     
    for (i = 0; i < G->vexnum; i++) {         
        for (j = 0; j < G->vexnum; j++) {             
            G->arcs[i][j] = 0;         
        }     
    }     
    for(i=0;i<G->vexnum;i++)     {         
        G->vexs[i]=i+1;     
    }     
    for (k = 0; k < G->arcnum; k++) {         
        scanf("%d%d", &v1, &v2);         
        getchar();         
        i = locate(*G, v1);         
        j = locate(*G, v2);         
        G->arcs[i][j] = 1;         
        G->arcs[j][i] = 1;     
    } 
}  

int visited[1000];  

void DepthFirstSearch(AMGraph *g, int v0) {     
    visited[v0] = 1;     
    for (int vj = 0; vj < g->vexnum; vj++) {         
        if (!visited[vj] && g->arcs[v0][vj] == 1) {             
            DepthFirstSearch(g, vj);         
        }     
    } 
}  

void TraverseGraph(AMGraph *g,int v0) {     
    for (int vi = 0; vi < g->vexnum; vi++) {         
        visited[vi] = 0;     
    }         
    DepthFirstSearch(g, v0); 
}  

int main() {     
    int v0,v1;     
    AMGraph G;     
    CreatMGraph(&G);     
    scanf("%d%d",&v0,&v1);     
    TraverseGraph(&G,v0);     
    if(visited[v1]==1)         
        printf("yes");     
    else         
        printf("no");     
    return 0; 
}