有向图强连通分量tarjan算法模板

struct node{    int u,to,next,w;}e[maxn*maxn];int id[maxn],q[maxn],dfn[maxn],low[maxn],num[maxn];int n,m,tsp,qe,cnt;void init(){    memset(head,-1,sizeof(head));    edge=0;}void addedge(int u,int v){    e[edge].u=u;    e[edge].to=v;    e[edge].next=head[u];    head[u]=edge++;}void tarjan(int u){    int i,v;    dfn[u]=low[q[qe++]=u]=++tsp;    for(i=head[u];i>=0;i=e[i].next)        if(!dfn[v=e[i].to])        {            tarjan(v);            low[u]=min(low[u],low[v]);        }        else        {            if(id[v]<0)            {              low[u]=min(low[u],dfn[v]);            }        }    if(low[u]==dfn[u])    {        ++cnt;        do{                v=q[--qe];                ++num[id[v]=cnt];        }while(v!=u);    }}void solve(){    int i;    tsp=qe=cnt=0;    for(i=0;i<=n;++i)        id[i]=-1,dfn[i]=0;    for(i=1;i<=n;++i)        if(!dfn[i])            tarjan(i);}