Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)
	nodes := make([]Node, n)

	for i := 0; i < n; i++ {
		nodes[i].list = make([]int, 0)
		nodes[i].d = -1
	}

	for i := 0; i < n; i++ {
		u := getNextInt(scanner)
		k := getNextInt(scanner)
		u--
		for ii := 0; ii < k; ii++ {
			v := getNextInt(scanner)
			v--
			nodes[u].list = append(nodes[u].list, v)
		}
	}

	queue := make([]int, n)
	queue[0] = 0
	nodes[0].d = 0
	d := 0
	i, j := 0, 1
	for i < j {
		d++
		prev := j
		for i < prev {
			for k, l := 0, len(nodes[queue[i]].list); k < l && i < n; k++ {
				if nodes[nodes[queue[i]].list[k]].d != -1 {
					continue
				}
				nodes[nodes[queue[i]].list[k]].d = d
				queue[j] = nodes[queue[i]].list[k]
				j++
			}
			i++
		}
	}

	for i := 0; i < n; i++ {
		fmt.Fprintln(writer, fmt.Sprintf("%d %d", i+1, nodes[i].d))
	}

	writer.Flush()
}

// Node ...
type Node struct {
	list []int
	d    int
}

C++: #include<iostream>
#include<vector>

int ptod[101]{};
int vertices_num;
std::vector<int> dest[101];
std::vector<int> visited_list;
void search();

int main()
{
	int vertex_tmp, dest_num, dest_tmp;

	std::cin >> vertices_num;
	for (int i = 1; i <= vertices_num; ++i)
	{
		std::cin >> vertex_tmp >> dest_num;
		for (int j = 0; j < dest_num; ++j)
		{
			std::cin >> dest_tmp;
			dest[vertex_tmp].push_back(dest_tmp);
		}
	}

	search();

	for (int i = 1; i <= vertices_num; ++i)
		std::cout << i << " " << ptod[i] << std::endl;

	return 0;
}

void search()
{
	int pre_size{ 0 };
	visited_list.push_back(1);
	bool visited[101]{ false, true };
	for (int i = 1; pre_size != visited_list.size(); ++i)
	{
		int now_size = visited_list.size();
		for (int j = pre_size; j < now_size; ++j)
			for (auto e : dest[visited_list[j]])
				if (!visited[e])
				{
					visited[e] = true;
					visited_list.push_back(e);
					ptod[e] = i;
				}
		pre_size = now_size;
	}
	for (int i = 1; i <= vertices_num; ++i)
		if (!visited[i])
			ptod[i] = -1;
	return;
}

C++: #include <bits/stdc++.h>
using namespace std;

int n;
vector < int > G[105];
int mc[105];

void bfs()
{
    queue < int > que;

    fill_n(mc, 105, -1);
    que.push(1);
    mc[1] = 0;
    
    while ( !que.empty() ) {
        int u = que.front(); que.pop();
        for ( auto &v : G[u] ) {
            if ( mc[v] == -1 ) {
                mc[v] = mc[u] + 1;
                que.push(v);
            }
        }
    }
}

int main()
{
    cin >> n;
    for ( int i = 0; i < n; i++ ) {
        int u, k;
        cin >> u >> k;
        for ( int j = 0; j < k; j++ ) {
            int v;
            cin >> v;
            G[u].push_back(v);
        }
    }
    
    bfs();

    for ( int i = 1; i <= n; i++ ) {
        cout << i << " " << mc[i] << endl;
    }

    return (0);
}