[백준/자바] 1260 - DFS와 BFS

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.*;

public class Main {

    static ArrayList<Integer>[] arr;
    static boolean[] visited;

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st = new StringTokenizer(br.readLine());
        int N = Integer.parseInt(st.nextToken());
        int M = Integer.parseInt(st.nextToken());
        int V = Integer.parseInt(st.nextToken());

        arr = new ArrayList[N + 1];
        for (int i = 1; i <= N; i++) {
            arr[i] = new ArrayList<>();
        }

        for (int i = 0; i < M; i++) {
            st = new StringTokenizer(br.readLine());
            int start = Integer.parseInt(st.nextToken());
            int end = Integer.parseInt(st.nextToken());

            arr[start].add(end);
            arr[end].add(start);
        }

        for (int i = 1; i <= N; i++) {
            Collections.sort(arr[i]);
        }

        visited = new boolean[N + 1];
        dfs(V);
        System.out.println();

        visited = new boolean[N + 1];
        bfs(V);
    }

    private static void dfs(int node) {
        System.out.print(node + " ");
        visited[node] = true;

        for (int i : arr[node]) {
            if (!visited[i])
                dfs(i);
        }
    }

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

        while (!queue.isEmpty()) {
            int now = queue.poll();
            System.out.print(now + " ");

            for (int i : arr[now]) {
                if (!visited[i]) {
                    visited[i] = true;
                    queue.add(i);
                }
            }
        }
    }
}