Tarjan 割点割边【模板】

 #include <algorithm>
 #include <cstring>
 #include <cstdio>

 using namespace std;

 const int N(+);
 int n,m,u,v;
 int head[N],sumedge;
 struct Edge
 {
     int to,next;
     Edge(int to=,int next=) :
         to(to),next(next){}
 }edge[N<<];

 void ins(int from,int to)
 {
     edge[++sumedge]=Edge(to,head[from]);
     head[from]=sumedge;
 }

 int dfn[N],low[N],tim;
 int cutpoint[N],cutedge[N],sum;

 void DFS(int now,int pre)
 {
     low[now]=dfn[now]=++tim;
     int sumtredge=,if_cutpoint=;
     for(int i=head[now];i!=-;i=edge[i].next)
         if((i^)!=pre)
         {
             int go=edge[i].to;
             if(!dfn[go])
             {
                 sumtredge++;
                 DFS(go,i);
                 if(low[go]>=dfn[now]) if_cutpoint=;
                 if(low[go]>dfn[now]) cutedge[i>>]=true;
                 low[now]=min(low[now],low[go]);
             }
             else low[now]=min(low[now],dfn[go]);
           }
     if(pre==-)
     {
         if(sumtredge>)  cutpoint[now]=true;
     }
     else if(if_cutpoint) cutpoint[now]=true;
 }

 int main()
 {
     /*freopen("made.txt","r",stdin);
     freopen("myout.txt","w",stdout);*/

     scanf("%d%d",&n,&m);
     sumedge=-; //使边之间更有关系
     memset(head,-,sizeof(head));
     for(int i=;i<=m;i++)
     {
         scanf("%d%d",&u,&v);
         ins(u,v);
         ins(v,u);
     }
     for(int i=;i<=n;i++)
         if(!dfn[i]) DFS(i,-);
     for(int i=;i<=n;i++)
         if(cutpoint[i]) printf("%d ",i);
     printf("\n");
     for(int i=;i<sumedge;i++)
         if(cutedge[i]) printf("%d ",i);
     return ;
 }