250320 단절점

@SuppressWarnings("unchecked")
public static void main(String[] args) throws IOException {
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	StringTokenizer st = new StringTokenizer(br.readLine());

	int vertices = Integer.parseInt(st.nextToken());
	int edges = Integer.parseInt(st.nextToken());

	List<Integer>[] adjacencyList = new ArrayList[vertices + 1];
	boolean[] isCutVertex = new boolean[vertices + 1];
	int[] discovered = new int[vertices + 1];
	int counter = 0;

	for (int i = 1; i <= vertices; i++) {
		adjacencyList[i] = new ArrayList<>();
		discovered[i] = -1;
	}

	for (int i = 0; i < edges; i++) {
		st = new StringTokenizer(br.readLine());
		int a = Integer.parseInt(st.nextToken());
		int b = Integer.parseInt(st.nextToken());
		adjacencyList[a].add(b);
		adjacencyList[b].add(a);
	}

	for (int i = 1; i <= vertices; i++) {
		if (discovered[i] == -1) {
			counter = findCutVertex(i, true, adjacencyList, isCutVertex, discovered, counter);
		}
	}

	StringBuilder sb = new StringBuilder();
	int count = 0;
	for (int i = 1; i <= vertices; i++) {
		if (isCutVertex[i]) {
			count++;
			sb.append(i).append(" ");
		}
	}
	System.out.println(count);
	if (count > 0) {
		System.out.println(sb.toString());
	}
}

private static int findCutVertex(int current, boolean isRoot, List<Integer>[] adjacencyList, boolean[] isCutVertex,
		int[] discovered, int counter) {
	discovered[current] = counter++;
	int ret = discovered[current];
	int childCount = 0;

	for (int next : adjacencyList[current]) {
		if (discovered[next] == -1) {
			childCount++;
			int subTree = findCutVertex(next, false, adjacencyList, isCutVertex, discovered, counter);
			if (!isRoot && subTree >= discovered[current]) {
				isCutVertex[current] = true;
			}
			ret = Math.min(ret, subTree);
		} else {
			ret = Math.min(ret, discovered[next]);
		}
	}
	if (isRoot) {
		isCutVertex[current] = childCount >= 2;
	}
	return ret;
}

출처:https://www.acmicpc.net/problem/11266