private static void findArticulationPoints(ArrayList<ArrayList<Integer>> adj, int N) {

boolean vis[] = new boolean[N];

int time[] = new int[N];

int low[] = new int[N];

int timer = 0;

boolean articulationPoints[] = new boolean[N];

for (int i = 0; i < N; i++) {

if (!vis[i]) {

dfs(i, -1, adj, vis, time, low, timer, articulationPoints);

}

}

for (int i = 0; i < N; i++) {

if (articulationPoints[i] == true)

System.out.println(i);

}

}

private static void dfs(int node, int par, ArrayList<ArrayList<Integer>> adj, boolean vis[], int time[], int low[], int timer, boolean[] articulationPoints) {

vis[node] = true;

time[node] = low[node] = timer++;

int child = 0;

for (Integer it : adj.get(node)) {

if (it == par)

continue;

if (!vis[it]) {

dfs(it, node, adj, vis, time, low, timer, articulationPoints);

low[node] = Math.min(low[node], low[it]);

if (low[it] >= time[node] && par != -1) {

articulationPoints[node] = true;

}

child++;

} else {

low[node] = Math.min(low[node], time[it]);

}

}

if (par != -1 && child > 1)

articulationPoints[node] = true;

}

public static void main(String args[]) {

int n = 5;

ArrayList<ArrayList<Integer>> adj = new ArrayList<ArrayList<Integer>>();

for (int i = 0; i < n; i++)

adj.add(new ArrayList<Integer>());

adj.get(0).add(1);

adj.get(1).add(0);

adj.get(0).add(2);

adj.get(2).add(0);

adj.get(1).add(2);

adj.get(2).add(1);

adj.get(1).add(3);

adj.get(3).add(1);

adj.get(3).add(4);

adj.get(4).add(3);

articulationPoint obj = new articulationPoint();

obj.findArticulationPoints(adj, n);

}