Tarjan

//记得每次清边vector<int>Edge[maxm];stack<int>S;int Dfn[maxn],Low[maxn],sccno[maxn],tclock,sccnt;//sccno代表某个点所在的强连通分量编号void tarjan(int u){    Dfn[u] = Low[u] = ++tclock;    S.push(u);    for(int i = 0;i < Edge[u].size();i++){        int v = Edge[u][i];        if(!Dfn[v]){            tarjan(v);            Low[u] = min(Low[u],Low[v]);        }        else if(!sccno[v]){            Low[u] = min(Low[u],Dfn[v]);        }    }    if(Low[u] == Dfn[u]){        sccnt ++;        int v = -1;        while(v != u){            v = S.top();            S.pop();            sccno[v] = sccnt;        }    }}void findscc(int n){    tclock = sccnt = 0;    //各种数组初始化    memset(Dfn,0,sizeof(Dfn));    memset(Low,0,sizeof(Low));    memset(sccno,0,sizeof(sccno));    for(int i = 1;i <= n;i++)        if(!Dfn[i]) tarjan(i);}