articulation points

///:-)
#include <bits/stdc++.h>
#define pb push_back
#define ll long long int
#define inf 2000000000
#define infLL 9000000000000000000
#define infULL 18446744073709551615
#define Aktaruzzaman using
#define pi (2.0*acos(0.0))
#define Pramanik namespace std;
#define vsort(v)   sort(v.begin(),v.end())
#define ull unsigned long long int
#define mem(a, b) memset(a, b, sizeof a)
#define cf 100009
#define MOD 1000000007
#define pii pair<int, int>

//int dx[]={0,1,0,-1};
//int dy[]={1,0,-1,0};
//int dx[]={1,1,0,-1,-1,-1,0,1};
//int dy[]={0,1,1,1,0,-1,-1,-1};

template <class T> inline T gcd(T a,T b){if(b==0)return a;return gcd(b,a%b);}
template< class T > inline T lcm(T a,T b) {a=abs(a);b=abs(b); return (a/gcd(a,b))*b;}
template <class T> inline T is_prime(T a){if(a<2|a==4)return false;if(a==2||a==3||a==5)return true; T g=(T)sqrt(a)+1; for(T i=2; i<=g; i++){if(a%i==0)return false;}return false;}
template <class T> inline T bigmod(T n,T p,T m){if(p==0)return 1; if(p%2)return ((n%m)*bigmod(n,p-1,m))%m; else {T c=bigmod(n,p/2,m);return ((c%m)*(c%m))%m;}}

Aktaruzzaman Pramanik

vector<int>a[1000], ans;
int disc[1001], low[1001], vis[1001], par[1001];
int discTime;

void dfs(int x){

    ++discTime;
    disc[x]=discTime;
    low[x]=discTime;
    int children=0;
    vis[x]++;

    for(int i=0; i<a[x].size(); i++){
        int y = a[x][i];
        if(vis[y]==-1){

            children++;
            par[y]=x;
            dfs(y);
            low[x]=min(low[x], low[y]);

            if(children>1 && par[x]==-1){
                ans.pb(x);
            }
            if(par[x]!=-1 && low[y]>=disc[x])ans.pb(x);

        }

        else if(y!=par[x]){
            low[x]=min(low[x], disc[y]);
        }
    }

}

int main()
{
    //freopen("input.txt","r",stdin)
    //freopen("output.txt","w",stdout)

    int n, m, i, j, k, x, y;

    scanf("%d%d", &n, &m);

    for(i=1; i<=m; i++){
        scanf("%d%d", &x, &y);
        a[x].pb(y);
        a[y].pb(x);
    }

    for(i=1; i<=n; i++){
        par[i]=-1;
        vis[i]=-1;
        disc[i]=0;
        low[i]=0;
    }
    discTime=0;
    for(i=1; i<=n; i++){
        if(vis[i]==-1)dfs(i);
    }

    printf("Articulation points are:\n");
    for(i=0; i<ans.size(); i++)printf("%d ",ans[i]);
    printf("\n");
    ans.clear();
    for(i=1; i<=n; i++)a[i].clear();
    cout<<"OK"<<endl;
    return main();

}