解法一：建树+广度优先遍历

设计好结点数据结构，边读入边建树，用 Map 保存结点防止重复创建同一编号的结点。建树后进行一次广度优先遍历计算每层的叶子结点数量。

import java.util.*;
import java.io.*;
public class Main {
    public static void main(String[] args) throws IOException {
        StreamTokenizer in = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));
        PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
        in.nextToken();
        int N = (int) in.nval;
        in.nextToken();
        int M = (int) in.nval;
        // 处理特殊情况
        if (M == 0) {
            out.println(N);
            out.flush();
            return;
        }
        // 建树
        Map<Integer, TreeNode> map = new HashMap();
        for (int i = 0, id, cnt; i < M; ++i) {
            in.nextToken();
            id = (int) in.nval;
            in.nextToken();
            cnt = (int) in.nval;
            TreeNode root = map.getOrDefault(id, new TreeNode(id, cnt));
            for (int j = 0, childId; j < cnt; ++j) {
                in.nextToken();
                childId = (int) in.nval;
                TreeNode childNode = map.getOrDefault(childId, new TreeNode(childId));
                map.put(childId, childNode);
                root.next.add(childNode);
            }
            map.put(id, root);
        }
        // 层序遍历
        Queue<TreeNode> queue = new LinkedList<>();
        queue.offer(map.get(1));
        ArrayList<Integer> ans = new ArrayList<>();
        while (!queue.isEmpty()) {
            int cnt = 0;
            int size = queue.size();
            for (int i = 0; i < size; ++i) {
                TreeNode root = queue.poll();
                if (root.next.isEmpty()) {
                    ++cnt;
                } else {
                    for (TreeNode node : root.next) {
                        queue.offer(node);
                    }
                }
            }
            ans.add(cnt);
        }
        for (int i = 0; i < ans.size() - 1; ++i) {
            out.print(ans.get(i) + " ");
        }
        out.println(ans.get(ans.size() - 1));
        out.flush();
    }
}
class TreeNode {
    int id;
    List<TreeNode> next;
    TreeNode(int id) {
        this.id = id;
        next = new ArrayList<>();
    }
    TreeNode(int id, int capacity) {
        this.id = id;
        next = new ArrayList<>(capacity);
    }
}