c++判断图连通性

判断图的连通性的最优算法是什么啊，用c＋＋怎么编码实现呢

#define NumberofVertices 20

struct Edge{
int dest;
struct Edge*link;
}

struct Vertex{
int data;
struct Edge* adj;
}

struct Vertex NodeTable[NumberofVertices];

int GetFirstNeighbor(int v)
{
if(v!=-1)
{
struct Edge* p=NodeTable[v].adj;
if(p)return p->dest;
}
return -1;
}

int GetNextNeighbor(int v,int w)
{
if(v!=-1)
{
struct Edge* p=NodeTable[v].adj;
while(p)
{
if(p->dest==w &&p->link)return p->link->dest;
else p=p->link;
}
}
return -1;
}

void DFS(int v,int visited[])
{
int w;
visited[v]=1;
w=GetFirstNeighbor(v);
while(w!=-1)
{
if(visited[w]==0)DFS(w,visited);
w=GetNextNeighbor(v,w);
}
}

int Isconect()
{
int i,x=0;
int n=NumberofVertices;
int* visited=(int*)malloc(sizeof(int)*n);
for(i=0;i<n;i++)visited[i]=0;
for(i=0;i<n;i++)
if(visited[i]==0)
{
DFS(i,visited);
x++;
}
free(visited);
if(x>1)
{printf("It is not connected!\n");return 1;}
else
printf("It is connected!\n");
return 0;
}