tarjan模板

void tarjan(int x)
{
	dfn[x]=low[x]=++num;
	stk.push(x);
	f[x]=1;
	for(int i=head[x];i;i=net[i])
	{
		if(!dfn[to[i]])
		{
			tarjan(to[i]);
			low[x]=min(low[x],low[to[i]]);
		}
		else if(f[to[i]])
		{
			low[x]=min(low[x],dfn[to[i]]);
		}
	}
	if(low[x]==dfn[x])
	{
		int y;
		++t;
		do
		{
			y=stk.top();
			stk.pop();
			f[y]=0;
			belong[y]=t;
			vl[t]+=v[y];
		}while(y!=x);
	}
}

void reb()
{
	for(int i=1;i<=n;i++)
	{
		for(int j=head[i];j;j=net[j])
		{
			if(belong[i]!=belong[to[j]]) add1(belong[i],belong[to[j]]);
		}
	}
}

//存边要从2开始存
void tarjan(int x,int in_edge)
{
	dfn[x]=low[x]=++num;
	for(int i=head[x];i;i=edge[i].next)
	{
		int y=edge[i].to;
		if(!dfn[y])
		{
			tarjan(y,i);
			low[x]=min(low[x],low[y]);
			if(low[y]>dfn[x])
			{
				bridge[i]=bridge[i^1]=1;
			}	
		}
		else if(i!=(in_edge^1))
		{
			low[x]=min(low[x],dfn[y]);
		}
	}
}

void tarjan(int now)
{
	dfn[now]=low[now]=++num;
	int flag=0;  
	for(int i=head[now];i;i=edge[i].next)
	{
		int y=edge[i].to;
		if(!dfn[y])
		{
			tarjan(y);
			low[now]=min(low[now],low[y]);
			if(low[y]>=dfn[now])
			{
				flag++;
				if(now!=root||flag>1) cut[now]=1;
			}	
		}
		else
		{
			low[now]=min(low[now],dfn[y]);
		}
	}
}