记录编号	367678	评测结果	AAAAAAAAAA
题目名称	备用交换机	最终得分	100
用户昵称	sxysxy	是否通过	通过
代码语言	C++	运行时间	0.002 s
提交时间	2017-02-01 13:03:13	内存使用	0.50 MiB

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <string>
#include <list>
#include <queue>
#include <vector>
#include <algorithm>
#include <cctype>
using namespace std;
namespace IO{
  char buf[1<<18], *fs, *ft;
  inline char readc(){
    return (fs==ft&&(ft=(fs=buf)+fread(buf,1,1<<18,stdin)),fs==ft)?EOF:*fs++;
  }
  inline int readint(){
    int r;char c;
    while(c = readc()){
      if(c >= '0' && c <= '9'){
        r = c^0x30;break;
      }else if(!(~c))return EOF;
    }
    while(isdigit(c = readc()))r = (r<<3)+(r<<1)+(c^0x30);
    return r;
  }
};using IO::readint;
vector<int> G[102];
int dfn[102], low[102], fa[102], cd[102], tim;
bool cut[102];
inline void addedge(int u, int v){
  G[u].push_back(v); G[v].push_back(u);
}
void tarjan(int u){
  dfn[u] = low[u] = ++tim;
  for(int i = 0; i < G[u].size(); i++){
    int v = G[u][i];
    if(!dfn[v]){
      fa[v] = u;
      cd[u]++;
      tarjan(v);
      low[u] = min(low[u], low[v]);
    }else{
      low[u] = min(low[u], dfn[v]);
    }
  }
  if(!fa[u] && cd[u] >= 2)cut[u] = true;
  if(fa[fa[u]] && low[u] >= dfn[fa[u]])cut[fa[u]] = true;
}
int main(){
  freopen("gd.in", "r", stdin);
  freopen("gd.out", "w", stdout);
  int n = readint();
  while(true){
    int x = readint();
    int y = readint();
    if(x == EOF || y == EOF)break;
    addedge(x, y);
  }
  vector<int> ans;
  for(int i = 1; i <= n; i++)if(!dfn[i])tarjan(i);
  for(int i = 1; i <= n; i++)if(cut[i])ans.push_back(i);
  printf("%d\n", ans.size());
  for(int i = 0; i < ans.size(); i++)printf("%d\n", ans[i]);
  return 0;
}