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参考题目:洛谷P3388
解析:
联赛完后统一更所有模板题题解。
代码:
#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define re register
#define gc getchar
#define pc putchar
#define cs const
inline int getint(){
re int num;
re char c;
while(!isdigit(c=gc()));num=c^48;
while(isdigit(c=gc()))num=(num<<1)+(num<<3)+(c^48);
return num;
}
cs int N=20004,M=100005;
int last[N],nxt[M<<1],to[M<<1],ecnt;
inline void addedge(int u,int v){
nxt[++ecnt]=last[u],last[u]=ecnt,to[ecnt]=v;
nxt[++ecnt]=last[v],last[v]=ecnt,to[ecnt]=u;
}
int dfn[N],low[N],dfs_clock;
bool cut[N];
inline void tarjan(int u,int root){
dfn[u]=low[u]=++dfs_clock;
int son=0;
for(int re e=last[u],v=to[e];e;v=to[e=nxt[e]]){
if(!dfn[v]){
tarjan(v,root);
low[u]=min(low[u],low[v]);
if(low[v]>=dfn[u]&&u!=root)cut[u]=true;
if(u==root)++son;
}
low[u]=min(low[u],dfn[v]);
}
if(son>=2&&u==root)cut[u]=true;
}
int n,m;
signed main(){
n=getint();
m=getint();
for(int re i=1;i<=m;++i){
int u=getint(),v=getint();
addedge(u,v);
}
int tot=0;
for(int re i=1;i<=n;++i){
if(!dfn[i])tarjan(i,i);
if(cut[i])++tot;
}
cout<<tot<<"\n";
for(int re i=1;i<=n;++i)if(cut[i])cout<<i<<" ";
return 0;
}