240524 DFS와 BFS

static class Node {
	int idx;
	Node next;

	public Node(int idx) {
		this.idx = idx;
	}

	public void insert(Node node) {
		if (idx > node.idx) {
			int tmp = idx;
			idx = node.idx;
			node.idx = tmp;
			node.next = this.next;
			next = node;
		} else if (next == null) {
			next = node;
		} else {
			next.insert(node);
		}
	}
}

static int n;
static Node[] graph;
static boolean[] visited;
static StringBuilder sb = new StringBuilder();

public static void main(String[] args) throws IOException {
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
	StringTokenizer st = new StringTokenizer(br.readLine());
	n = Integer.parseInt(st.nextToken());
	graph = new Node[n + 1];
	int m = Integer.parseInt(st.nextToken());
	int v = Integer.parseInt(st.nextToken());

	for (int i = 0; i < m; i++) {
		st = new StringTokenizer(br.readLine());
		int from = Integer.parseInt(st.nextToken());
		int to = Integer.parseInt(st.nextToken());
		if (graph[from] == null) {
			graph[from] = new Node(to);
		} else {
			graph[from].insert(new Node(to));
		}
		if (graph[to] == null) {
			graph[to] = new Node(from);
		} else {
			graph[to].insert(new Node(from));
		}
	}

	visited = new boolean[n + 1];
	dfs(v);

	sb.append('\n');
	visited = new boolean[n + 1];
	bfs(v);

	bw.write(sb.toString());
	bw.flush();
	bw.close();
}

private static void bfs(int v) {
	Queue<Integer> queue = new LinkedList<>();
	queue.add(v);
	visited[v] = true;
	sb.append(v).append(' ');

	while (!queue.isEmpty()) {
		int cur = queue.poll();

		for (Node tmp = graph[cur]; tmp != null; tmp = tmp.next) {
			if (visited[tmp.idx]) continue;
			sb.append(tmp.idx).append(' ');
			visited[tmp.idx] = true;
			queue.add(tmp.idx);
		}
	}
}

private static void dfs(int cur) {
	visited[cur] = true;
	sb.append(cur).append(' ');
	for (Node tmp = graph[cur]; tmp != null; tmp = tmp.next) {
		if (visited[tmp.idx]) continue;
		dfs(tmp.idx);
	}
}

출처:https://www.acmicpc.net/problem/1260