Go: package main

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

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
type Queue struct {
	arr []int
}

func (q *Queue) push(v int) {
	q.arr = append(q.arr, v)
}

func (q *Queue) pop() int {
	res := q.arr[0]
	q.arr = q.arr[1:]
	return res
}

func (q *Queue) isEmpty() bool {
	return len(q.arr) == 0
}

func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	G := make([][]int, N)
	for i := 0; i < N; i++ {
		u, k := sc.nextInt()-1, sc.nextInt()
		for j := 0; j < k; j++ {
			G[u] = append(G[u], sc.nextInt()-1)
		}
	}
	var q Queue
	seen := make([]int, N)
	for i := 0; i < N; i++ {
		seen[i] = -1
	}
	var search func(cur int)
	search = func(cur int) {
		for i := 0; i < len(G[cur]); i++ {
			next := G[cur][i]
			if seen[next] == -1 {
				q.push(next)
				seen[next] = seen[cur] + 1
			}
		}
	}
	q.push(0)
	seen[0] = 0
	for !q.isEmpty() {
		search(q.pop())
	}

	for i := 0; i < N; i++ {
		fmt.Fprintln(wtr, i+1, seen[i])
	}
	wtr.Flush()
}

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

using namespace std;

static const int N = 100;
static const int WHITE = 0;
static const int GREY = 1;
static const int BLACK = 2;

int n, m[N][N];
bool visited[N];
int d[N], dist;


void bfs(int i){
	queue<int> q; q.push(i);
	visited[i] = true;

	while (!q.empty()) {
		int u = q.front(); q.pop();
		for (int v = 0; v < n; ++v) {
			if (!visited[v] && m[u][v]){
				d[v] = d[u] + 1;
				visited[v] = true;
				q.push(v);
			}
		}
	}
}


void search(){
	for (int i = 0; i < n; ++i) {
		d[i] = -1;
		visited[i] = false;
	}
	d[0] = 0;
	for (int i = 0; i < n; ++i) {
		if (!visited[i]) bfs(i);
	}
	for (int i = 0; i < n; ++i)	cout << i + 1 << " " << d[i] << endl;
}


int main()
{
	cin >> n;

	for (int i = 0; i < n; ++i) {
		for (int j = 0; j < n; ++j) m[i][j] = 0;
	}

	for (int i = 0; i < n; ++i) {
		int u, d; cin >> u >> d;
		for (int j = 0; j < d; ++j) {
			int v; cin >> v;
			m[u - 1][v - 1] = 1;
		}
	}

	search();

	return 0;
}

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

using namespace std;
static const int N = 100;
static const int INFTY = (1<<21);

int n,M[N][N];
int d[N];

void bfs(int s){
  queue<int> q;
  q.push(s);
  for(int i = 0; i < n; i++) d[i] = INFTY;
  d[s] = 0;
  int u;
  while(!q.empty()){
    u = q.front();
    q.pop();
    for(int v=0;v<n;v++){
      if(M[u][v] == 0) continue;
      if(d[v]!=INFTY) continue;
      d[v] = d[u] + 1;
      q.push(v);
    }
  }
  for(int i = 0; i<n; i++){
    cout << i+1 << " " << ( (d[i] == INFTY) ? (-1) : d[i] ) << endl;
  }
}

int main(){
  int u,k,v;

  cin >> n;
  for(int i=0;i<n;i++){
    for(int j = 0; j < n; j++) M[i][j] = 0;
  }

  for(int i = 0; i < n; i++){
    cin >> u >> k;
    u--;
    for(int j = 0; j<k; j++){
      cin>>v;
      v--;
      M[u][v] = 1;
    }
  }
  bfs(0);

  return 0;
}

C++: #include <iostream>
#include <queue>
#include <vector>
using namespace std;

int main () {
    int n ;
    cin >> n;

    vector <int> v[n + 1];

    for (int i = 1; i <= n; i++) {
        int x, no;
        cin >> x >> no;
        for(int j = 0; j < no; j++) {
            int temp;
            cin >> temp;
            v[x].push_back(temp);
        }
    }

	queue <int> q;
	q.push(1);
	
	int dis[n + 1];
	for (int i = 0; i <= n; i++)
		dis[i] = -1;
	dis[1] = 0;
		
	bool vis[n + 1] = {0};
    vis[1] = 1;
	while (!q.empty()) {
		for (int i = 0; i < v[q.front()].size(); i++) {
			int temp = v[q.front()][i];
			if (!vis[temp]) {
				q.push(temp);
				vis[temp] = 1;
				dis[temp] = dis[q.front()] + 1;
			}	
		}
		q.pop();
	}
	
	for (int i = 1; i <= n; i++)
		cout << i << ' ' << dis[i] << '\n';
}

C++: #include <iostream>
#include <queue>
#include <algorithm>
using namespace std;

int M[101][101], d[101], n;

void set()
{
	int u, k, v;
	for (int i = 0; i < n; i++) {
		cin >> u >> k;
		for (int j = 0; j < k; j++) {
			cin >> v;
			M[u][v] = 1;
		}
	}

	for (int i = 1; i <= n; i++)
		d[i] = -1;
}

void bfs(int x)
{
	queue<int> Q;

	Q.push(x);
	d[x] = 0;

	while (!Q.empty()) {
		int u = Q.front();
		for (int i = 1; i <= n; i++) {
			if (M[u][i] == 1 && d[i] == -1) {
				Q.push(i);
				d[i] = d[u] + 1;	
			}
		}
		Q.pop();
	}
}

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);

	cin >> n;
	set();

	bfs(1);

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

	return 0;
}

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

static const int N = 100;
static const int INFTY = (1 << 21);

int n, M[N][N];
int d[N];

void bfs(int s)
{
    std::queue<int> q;
    q.push(s);
    for (int i = 0; i < n; i++)
    {
        d[i] = INFTY;
    }
    d[s] = 0;
    int u;
    while (!q.empty())
    {
        u = q.front();
        q.pop();
        for (int v = 0; v < n; v++)
        {
            if (M[u][v] == 0)
            {
                continue;
            }
            if (d[v] != INFTY)
            {
                continue;
            }

            d[v] = d[u] + 1;
            q.push(v);
        }
    }
    for (int i = 0; i < n; i++)
    {
        std::cout << i + 1 << " " << ((d[i] == INFTY) ? (-1) : d[i]) << std::endl;
    }
}

int main() 
{
    int u, k, v ;
    std::cin >> n ;
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < n; j++)
        {
            M[i][j] = 0 ;
        }
        
    }
    for (int i = 0; i < n; i++)
    {
        std::cin >> u >> k ;
        u--;
        for (int j = 0; j < k; j++)
        {
            std::cin >> v ;
            v-- ;
            M[u][v] = 1 ;
        }
        
    }
    
    bfs(0) ;
    return 0 ;
}

C++: #include <iostream>
#include <cstdio>
#include <cstring>
#include <queue>
using namespace std;
const int maxx = 110;
int n, m[maxx][maxx];
int u, num, v;
int flag[maxx];
int d[maxx];


void bfs() {
	queue<int>q;

	q.push(1);
	d[1] = 0;
	while (!q.empty()) {
		int u = q.front();
		q.pop();
		for (int i = 2; i <= n; i++) {
			if (m[u][i] == 1 && flag[i] == 0) {
				// ?????°???????????????
				flag[i] = 1;
				// ??´??°??????
				d[i] = d[u] + 1;
				// ?????\??????
				q.push(i);
			}
		}
	}
}
int main()
{

	scanf("%d", &n);
	memset(m, 0, sizeof(m));
	for (int i = 1; i <= n; i++) {
		scanf("%d %d", &u, &num);

		// ????§????
		flag[i] = 0;
		d[i] = -1;
		for (int j = 1; j <= num; j++) {
			scanf("%d", &v);
			m[u][v] = 1;
		}
	}
	bfs();
	for (int i = 1; i <= n; i++) {
		printf("%d %d\n", i, d[i]);
	}
	return 0;
}