Kosaraju

编辑器加载中...

 

#define MAXNODE 

typedef struct NODE
{
    int num;
    struct Node *next;
}Node;
typedef Node* Graph[MAXNODE];


//--------Build_Graph & Free_Graph-------------
Graph G,GT;
int nodenum,edgenum;
void Build_Graph(Graph &G,Graph &GT)
{
    int nodeone,nodetwo;
    Node *p;
    memset(G,0,sizeof(G));
    memset(GT,0,sizeof(GT));
    for(int i=1;i<=edgenum;i++)
    {
        scanf("%d %d",&nodeone,&nodetwo);
        p=(Node*)malloc(sizeof(Node));
        p->num=nodetwo;
        p->next=G[nodeone];

        p=(Node*)malloc(sizeof(Node));
        p->num=nodeone;
        p->next=G[nodetwo];
    }
}
void Free_Graph(Graph &G,Graph &GT)
{
    Node *p,*next;
    int i;
    for(i=1;i<=nodenum;i++)
    {
        p=G[i];
        while(p)
        {
            next=p->next;
            free(p);
            p=next;
        }
        p=GT[i];
        while(p)
        {
            next=p->next;
            free(p);
            p=next;
        }
    }
}

//-------Kosaraju---------------
bool is_visited[MAXNODE];
int visit_order[MAXNODE];
int id_scc[MAXNODE];
void Fir_DFS(int i,int &order)
{
    is_visited[i]=true;
    for(Node *p=G[i];p;p=p->next)
    {
        int next=p->num;
        if(false==is_visited[next])
            Fir_DFS(next,order);
    }
    visit_order[++order]=i;
}
void Sec_DFS(int i,int id)
{
    is_visited[i]=true;
    for(Node *p=GT[i];p;p=p->next)
    {
        int next=p->num;
        if(false==is_visited[next])
            Sec_DFS(next,id);
    }
    id_scc[i]=id;
}

int Kosaraju()
{
    int order=0;
    memset(is_visited,false,sizeof(is_visited));
    for(int i=1;i<=nodenum;i++)
    {
        if(false==is_visited[i])
            Fir_DFS(i,order);
    }

    int cnt_scc=0;
    memset(is_visited,false,sizeof(is_visited));
    for(int i=nodenum;i>0;i--)
    {
        if(false==is_visited[visit_order[i]])
            Sec_DFS(visit_order[i],++cnt_scc);
    }
    
    return cnt_scc;
}