题意不懂啊。。。。。。

只知道求割点。

#include 
    
     using namespace std;typedef long long LL;typedef unsigned long long ULL;typedef pair
     
      PII;const double eps=1e-5;const double pi=acos(-1.0);const int mod=1e9+7;const int INF=0x3f3f3f3f;const int N=1e4+10;const int M=2e4+10;struct Edge{    int to;    int next;};Edge q[M*2];int head[M*2],tol,n,m;int dfn[N],low[N];int ind,top;bool flag[N],vis[N];void Tarjan(int u,int pre){    int v;    int son=0;    low[u]=dfn[u]=ind++;    vis[u]=true;    for(int i=head[u];i!=-1;i=q[i].next)    {        v=q[i].to;        if(v==pre)            continue;        if(!dfn[v])        {            son++;            Tarjan(v,u);            low[u]=min(low[v],low[u]);            if(u!=pre&&low[v]>=dfn[u])                flag[u]=true;        }        else            low[u]=min(low[u],dfn[v]);    }    if(pre==u&&son>1)        flag[u]=true;}void init(){    tol=0;    memset(head,-1,sizeof(head));}void add(int u,int v){    q[tol].to=v;    q[tol].next=head[u];    head[u]=tol++;}int main(){    int T,cas=1;//freopen("D:\\in.txt","r",stdin);    scanf("%d",&T);    while(T--)    {        scanf("%d%d",&n,&m);        init();        while(m--)        {            int u,v;            scanf("%d%d",&u,&v);            add(u,v);            add(v,u);        }        memset(dfn,0,sizeof(dfn));        memset(low,0,sizeof(low));        memset(flag,0,sizeof(flag));        memset(vis,0,sizeof(vis));        ind=1;        int ans=0;        Tarjan(1,1);        for(int i=1;i<=n;i++)            if(flag[i])            {              //  printf("%d\n",i);                ans++;            }        printf("Case %d: %d\n",cas++,ans);    }    return 0;}