暑假集训day2

#include<cstdio>
#include<iostream>
#include<cstring>
#include<algorithm>
#include<vector>
#include<map>
using namespace std;
const int maxn=500010;
int dfn[maxn],low[maxn],t=0,n,m,ans=0;
bool cut[maxn];
vector<int>g[maxn];
inline int read(){
    int num=0,t=1;char c=getchar();
    while(c>‘9‘||c<‘0‘){if(c==‘-‘)t=-1;c=getchar();}
    while(c<=‘9‘&&c>=‘0‘){num=num*10+c-‘0‘;c=getchar();}
    return num*t;
}
void add(int x,int y){
    g[x].push_back(y);g[y].push_back(x);
}
void tarjan(int x,int fa){
    int child=0;dfn[x]=low[x]=++t;
    for(int i=0;i<g[x].size();i++){
        int y=g[x][i];if(y==fa)continue;
        if(!dfn[y]){
            child++;
            tarjan(y,x);
            low[x]=min(low[x],low[y]);
            if(low[y]>=dfn[x])cut[x]=true;
        }
        else low[x]=min(low[x],dfn[y]);
    }
    if(low[x]==dfn[x]&&fa!=-1)ans++;
    if(fa==-1&&child<=1)cut[x]=false;
}
int main()
{
    n=read();m=read();
    for(int i=1;i<=m;i++){
        int x,y;x=read();y=read();add(x,y);
    }
    memset(dfn,0,sizeof(dfn));memset(cut,0,sizeof(cut));
    for(int i=1;i<=n;i++)if(!dfn[i])tarjan(i,-1);
    for(int i=1;i<=n;i++)if(cut[i])printf("%d ",i);
    puts("");printf("%d\n",ans);
    return 0;
}

#include<iostream>
#include<cstdio>
using namespace std;
int n,m,a[1010]={0};
int main()
{
    cin>>n;
    for(int i=1;i<=n;i++){cin>>m;a[m]=1;}
    m=0;
    for(int i=1;i<=1000;i++)if(a[i])m++;
    cout<<m<<"\n";
    for(int i=1;i<=1000;i++)if(a[i])cout<<i<<" ";
    return 0;
}