Tarjan

模板 转自https://blog.youkuaiyun.com/nothi/article/details/7739741

#include <iostream>
#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
using namespace std;
const int maxn=110000;//顶点个数
const int maxm=210000;//边个数
const int GRAY = 0;
const int WHITE =-1;
const int BLACK = 1;
typedef struct Edge
{
   int s,e,next;
}Edge;
typedef struct Adj{
    int edge_sum;
    int head[maxn];
    Edge edge[maxn];
    void init()
    {
        edge_sum=0;
        memset(head,-1,sizeof(head));
    }
    void add_edge(int a,int b){
        edge[edge_sum].s=a;
        edge[edge_sum].e=b;;
        edge[edge_sum].next=edge_sum;
        head[a]=edge_sum++;

    }
}Adj;
typedef struct Tarjan{
    int n;
    int *head;
    Adj *adj;
    Edge *edge;

    int cnt,top,cur;
    int dfn[maxn];
    int low[maxn];
    int stack[maxn];
    int belong[maxn];

    void initial(Adj *_adj,int _n){
        n=_n;
        adj=_adj;
        head=(*adj).head;
        edge=(*adj).edge;
    }
    void solve()
    {
        memset(dfn,-1,sizeof(dfn));
        memset(color,WHITE,sizeof(color));
        top=cnt=top=0;
        for(int i=0;i<n;i++)
        {
            if(color[i]==WHITE)
                Tarjan(i);
        }
    }
    void Tarjan(int i)
    {
        int j=head[i];
        color[i]=GRAY;
        stack[top++]=i;
        dfn[i]=low[i]=++cnt;
        while(j!=-1)
        {
            int u=edge[j].e;
            if(color[u]==WHITE)
            {
                Tarjan(u);
                low[i]=min(low[i],low[u]);
            }
            else if(color[u]==GRAY)
            {
                low[i]=min(low[i],dfn[u]);
            }
            j=edge[j].next;

        }
        color[i]=BLACK;
        if(low[i]==dfn[i])
        {
            do{
                j=stack[top--];
                belong[j]=cnt;
            }while(i!=j)
        }
        ++cnt;
    }

}