【算法模板】Tarjan求割点

#include<iostream>
#include<vector>

using namespace std;

const int MAXN=1001;

vector<int> g[10001];
int n,m,Intex,ans,dfn[MAXN],low[MAXN];
bool iscp[MAXN];

void find_cutpoint(int u,int fa)
{
    int child=0;
    dfn[u]=low[u]=++Intex;
    for(int i=0;i<g[u].size();i++)
    {
        int v=g[u][i];
        if(dfn[v]==0)
        {
            child++;
            find_cutpoint(v,u);
            low[u]=min(low[u],low[v]);
            if(low[v]>=dfn[u])iscp[u]=true;
            else low[u]=min(low[u],dfn[v]);
        }
    }
    if(fa<0&&child==1)iscp[u]=false;
}

int main()
{
    cin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        int x,y;
        cin>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    find_cutpoint(1,-1);
    for(int i=1;i<=n;i++)
    {
        if(iscp[i])
        {
            cout<<i<<" ";
            ans++;
        }
    }
    cout<<endl<<ans;
    return 0;
}