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模板题,无程序说明
Code:
#include<bits/stdc++.h>
#define rep(i,j,k) for(int i=j;i<=k;i++)
using namespace std;
template<typename T> void read(T &num){
char c=getchar();num=0;T f=1;
while(c<'0'||c>'9'){if(c=='-')f=-1;c=getchar();}
while(c>='0'&&c<='9'){num=(num<<3)+(num<<1)+(c^48);c=getchar();}
num*=f;
}
template<typename T> void qwq(T x){
if(x>9)qwq(x/10);
putchar(x%10+'0');
}
template<typename T> void write(T x){
if(x<0){x=-x;putchar('-');}
qwq(x);
}
int ans[20010];
struct wzy{
int nxt,vertice;
}edge[200010];
int head[20010];int len=0;
inline void add_edge(int x,int y){
edge[++len].nxt=head[x];edge[len].vertice=y;head[x]=len;
return;
}
int low[20010];int dfn[20010];bool iscut[20010];int siz=0;
inline void tarjan(int son,int father){
low[son]=dfn[son]=++siz;
int coun=0;
for(register int i=head[son];i;i=edge[i].nxt){
int nop=edge[i].vertice;
if(!dfn[nop]){
tarjan(nop,father);
low[son]=min(low[son],low[nop]);
iscut[son]|=(low[nop]>=dfn[son]&&son!=father);
coun+=(son==father);
}
low[son]=min(low[son],dfn[nop]);
}
iscut[son]|=(son==father&&coun>=2);
return;
}
int main(){
int n,m;read(n);read(m);
rep(i,1,m){
int x,y;read(x);read(y);
add_edge(x,y);add_edge(y,x);
}
rep(i,1,n){
if(!dfn[i])tarjan(i,i);
}
int ans_len=0;
rep(i,1,n){
if(iscut[i])ans[++ans_len]=i;
}
write(ans_len);putchar('\n');
rep(i,1,ans_len){write(ans[i]);putchar((i==ans_len)?'\n':' ');}
return 0;
}