Tarjan 割点割边【模板】

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

using namespace std;

const int N(100000+15);
int n,m,u,v;
int head[N],sumedge;
struct Edge
{
    int to,next;
    Edge(int to=0,int next=0) :
        to(to),next(next){}
}edge[N<<1];

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=0,if_cutpoint=0;
    for(int i=head[now];i!=-1;i=edge[i].next)
        if((i^1)!=pre)
        {
            int go=edge[i].to;
            if(!dfn[go])
            {
                sumtredge++;
                DFS(go,i);
                if(low[go]>=dfn[now]) if_cutpoint=1;
                if(low[go]>dfn[now]) cutedge[i>>1]=true;
                low[now]=min(low[now],low[go]);
            }
            else low[now]=min(low[now],dfn[go]);
          }
    if(pre==-1)
    {
        if(sumtredge>1)  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=-1; //使边之间更有关系
    memset(head,-1,sizeof(head));
    for(int i=1;i<=m;i++)
    {
        scanf("%d%d",&u,&v);
        ins(u,v);
        ins(v,u);
    }
    for(int i=1;i<=n;i++) 
        if(!dfn[i]) DFS(i,-1);
    for(int i=1;i<=n;i++)
        if(cutpoint[i]) printf("%d ",i);
    printf("
");
    for(int i=0;i<sumedge;i++)
        if(cutedge[i]) printf("%d ",i);
    return 0;
}