题目
思路
tarjan求割点
不会的戳(不知道好不好自己康康吧)
(Code)
#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<algorithm>
#define min_(a,b) a>b?b:a;
#define MAXN 100010
int n,m,cnt,id;
int head[MAXN];
int dfn[MAXN],low[MAXN];
bool cut[MAXN];
struct Edge{
int next,to;
}edge[200001];//无向图
inline int read(){
int x=0;bool f=0;char c=getchar();
while(c<'0'||c>'9'){if(c=='-')f=!f;c=getchar();}
while(c>='0'&&c<='9'){x=x*10+c-'0';c=getchar();}
return f?-x:x;
}
void add_edge(int from,int to){
edge[++cnt].to=to,edge[cnt].next=head[from],head[from]=cnt;
}
void tarjan(int u,int father){
dfn[u]=low[u]=++id;
int ch=0;
for(int i=head[u];i;i=edge[i].next){
int x=edge[i].to;
if(!dfn[x]){
tarjan(x,father);
low[u]=min_(low[u],low[x]);
if(low[x]>=dfn[u]&&u!=father) cut[u]=1;
if(u==father) ch++;
}
low[u]=min_(low[u],dfn[x]);
}
if(ch>=2&&u==father) cut[u]=1;
}
int main(){
n=read(),m=read();
int u,v;
for(int i=1;i<=m;++i){
u=read(),v=read();
add_edge(u,v),add_edge(v,u);
}
for(int i=1;i<=n;++i){
if(!dfn[i]) tarjan(i,i);
}
int tot=0;
for(int i=1;i<=n;++i){
if(cut[i]) tot++;
}
printf("%d
",tot);
for(int i=1;i<=n;++i){
if(cut[i]) printf("%d ",i);
}
puts("");
return 0;
}