邻接表写法与算法基础课y总教的写法有所区别，这样子写更方便排序

import java.util.*;

public class Main {
    static int N = 100010;
    static int n,m;
    static boolean[] st = new boolean[N];
    static List<Integer>[] l = new ArrayList[N];
    static int[] path = new int[N];
    static int idx1;
    static int idx2;

    public static void dfs(int u) {
        path[idx1 ++] = u;
        st[u] = true;
        for (int i:l[u]) {
            if (!st[i]) {
                dfs(i);
                st[i] = false;//恢复现场
            }
        }
    }
    public static void bfs(int u) {
        Queue<Integer> q = new LinkedList<>();
        q.offer(u);
        st[u] = false;
        while (q.size() != 0) {
            int t = q.remove();
            path[idx2 ++] = t;
            for (int i:l[t]) {
                if (!st[i]) {
                    q.offer(i);
                    st[i] = true;
                }
            }
        }
    }
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();
        m = sc.nextInt();

        //初始化邻接表
        for (int i = 1;i <= n;i ++) l[i] = new ArrayList<>();

        //建图
        for (int i = 1;i <= m;i ++) {
            int a = sc.nextInt();
            int b = sc.nextInt();
            l[a].add(b);
        }

        //排序
        for (int i = 1;i <= n;i ++) Collections.sort(l[i]);

        dfs(1);
        for (int i = 0;i < n;i ++) System.out.print(path[i] + " ");
        System.out.println();

        Arrays.fill(st, false);
        bfs(1);
        for (int i = 0;i < n;i ++) System.out.print(path[i] + " ");
    }
}