強連通模板（Tarjan)

使用說明：需要鄰接表模板 ，頭文件string.h 宏定義#define CLR(arr,v) memset(arr,v,sizeof(arr))

const int M = 105 ;
Graph<M,M*M> g;
int Connect[M],Low[M],Ind[M],Stack[M],InStack[M],ConnectNum,top,ind;

void Dfs(int cur)
{
	Low[cur] = Ind[cur] = ++ind;
	Stack[top++] = cur;
	InStack[cur] = true;
	for(int i = g.H[cur]; i != -1; i = g.Next[i])
	{
		if(!Ind[ g.Num[i] ])
		{
			Dfs(g.Num[i]);
			Low[cur] = min(Low[cur],Low[ g.Num[i] ]);
		}
		else if(InStack[ g.Num[i] ])
		{
			Low[cur] = min(Low[cur],Ind[ g.Num[i] ]);
		}
	}
	if(Low[cur] == Ind[cur])
	{
		ConnectNum++;
		int s;
		do{
			s = Stack[--top];
			Connect[s] = ConnectNum;
			InStack[s] = false;
		}while(cur != s);
	}
}

int Tarjan(int n)
{
	CLR(Ind,0);
	CLR(InStack,false);
	ConnectNum = top = ind = 0;
	for(int i = 1;i <= n;++i)
		if(!Ind[i]) Dfs(i);
	return ConnectNum;
}