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++: #define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using graph = vector<vector<ll>>;
graph g;
ll n;
int main(){
    cin >> n;
    g.resize(n);
    for (ll i = 0; i < n; i++) {
        ll u, k; cin >> u >> k;
        for (ll j = 0; j < k; j++) {
            ll x; cin >> x;
            g[i].push_back(x-1);
        }
    }

    vector<ll> dist(n, -1);
    queue<ll> que;
    dist[0] = 0, que.push(0);
    while(!que.empty()){
        ll v = que.front(); que.pop();
        for(ll nv : g[v]){
            if(dist[nv] == -1){
                dist[nv] = dist[v] + 1;
                que.push(nv);
            }
        }
    }
    for (ll i = 0; i < n; i++)  printf("%lld %lld\n", i+1, dist[i]);
        
    return 0;
}

C++: #include<iostream>
#include<queue>
using namespace std;
int n,u,k,v,**M;

void bfs(int src)
{
  int D[100];
  for(int i=0;i<100;i++)
    D[i]=-1;
  queue<int>Q;
  Q.push(src);
  D[src]=0;
  while(!Q.empty())
    {
      int cur=Q.front();
      Q.pop();
     // cout<<cur+1<<' '<<D[cur]<<endl;
       for(int dst=0;dst<n;dst++)
	{
	  if(M[cur][dst]==1&&D[dst]==-1)
	    {
	      D[dst]=D[cur]+1;
	      Q.push(dst);
	    }
    }
    }
    for(int i=0;i<n;i++)
        cout<<i+1<<' '<<D[i]<<endl;
}

int main()
{
  //int n,u,k,v,**M;
  cin>>n;
  M=new int*[n];
  for(int i=0;i<n;i++)
    {
      M[i]=new int[n];
      for(int j=0;j<n;j++)
	M[i][j]=0;
    }
  int count=0;
  while(count<n)
    {
      count++;
      cin>>u>>k;
      for(int i=0;i<k;i++)
	{
	  cin>>v;
	  M[u-1][v-1]=1;
	}
    }
    bfs(0);
  delete M;
}

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

int a[100][100];
int n;
int D[100];
void bfs(int src) {
	queue<int> Q;
	Q.push(src);
	D[src] = 0;
	while (! Q.empty()) {
		int cur = Q.front();
		Q.pop();
		for (int dst=0; dst<n; ++dst) {
			if (a[cur][dst] == 1 && D[dst] == -1) {
				D[dst] = D[cur]+1;
				Q.push(dst);
			}
		}
	}
}

int main() {
	cin >> n;
	int p,q,r;
	for (int i=0; i<n; ++i) {
		cin >> p >> q;
		D[i] = -1;
		for (int i=0; i<q; ++i) {
			cin >> r;
			a[p-1][r-1] = 1;
		}
	}
	bfs(0);
	for (int i=0; i<n; ++i) {
		cout << i+1 << " " << D[i] << endl;
	}
}

C++: #include <stdio.h>
#include <iostream>
using namespace std;

class Adjl{
private:
	int u;
	int k;
	Adjl **next;
	int check_id;
public:
	Adjl(int u);
	~Adjl(){ if (next != NULL) delete[] next; }
	void setV(int k, Adjl *vk);
	int breadthFirstSearch(int id);
	void print(int id);
};

Adjl::Adjl(int u)
{
	this->u = u;
	k = 0;
	next = NULL;
	check_id = 0;
}

void Adjl::setV(int k, Adjl *vk)
{
	if (this->k == 0) next = new Adjl*[k];
	next[this->k] = vk;
	(this->k)++;
}

int Adjl::breadthFirstSearch(int id)
{
	if (id == check_id) return -1;
	else check_id = id;

	if (id == this->u) return 0;

	int d_min = -1;
	for (int i = 0; i < k; i++) {
		int d = next[i]->breadthFirstSearch(id);
		if (d == -1) continue;
		if (d_min == -1) d_min = d + 1;
		else d_min = min(d + 1, d_min);
	}
	return d_min;
}

void Adjl::print(int id)
{
	cout << id << " " << breadthFirstSearch(id) << endl;
}

int main(void)
{
	int n;
	cin >> n;
	
	Adjl **adjl = new Adjl*[n];
	int check[100] = {0};

	for (int i = 0; i < n; i++) {
		int u, k;
		cin >> u >> k;
		if (check[i] == 0) {
			adjl[i] = new Adjl(u);
			check[i] = 1;
		}
		check[i] = 1;
		for (int j = 0; j < k; j++) {
			int vk;
			cin >> vk;
			if (check[vk - 1] == 0) {
				adjl[vk - 1] = new Adjl(vk);
				check[vk - 1] = 1;
			}
			adjl[i]->setV(k, adjl[vk - 1]);
		}
	}

	for (int i = 1; i <= n; i++) {
		adjl[0]->print(i);
	}

	delete[] adjl;
	return 0;
}

C++: #include <iostream>
#include <stdio.h>


int map_max;
int map[110][110];
int rows;
int cols[110];
int howfar[100];
int far;
int visited[100];

void get_map();
void print_map();
int search(int node, int far);
void print_result();
void check_result();

int main()
{

  get_map();
  //print_map();
  search(1, 0);
  check_result();
  print_result();
  return 0;
}

void check_result()
{
  for(int i=1;i<map_max;i++)
    {
      if(howfar[i]==0)
	{
	  howfar[i]=-1;
	}
    }
}

void print_result()
{
  for(int i=0;i<map_max;i++)
    {
      std::cout << i+1 << " " << howfar[i] << std::endl;
    }
}

void get_map()
{

  int k;
  scanf("%d", &map_max);//<100

  for(int i=0;i<map_max;i++)
    {
      scanf("%d", &k);
      scanf("%d", &cols[i]);
      for(int j=0;j<cols[i];j++)
	{
	  map[i][j]=0;
	  scanf("%d", &map[i][j]);
	}
    }

  
  return ;
}

void print_map()
{
  for(int i=0;i<map_max;i++)
    {
      for(int j=0;j<cols[i];j++)
	{
	  printf("%d", map[i][j]);
	}
      puts("");
    }
return ;
}
int search(int node, int far)
{
  if(visited[node-1] == 1)
    {
      if(howfar[node-1]>far)
	{
	  howfar[node-1]=far;
	}
      return -1;
    }
  else
    {
      howfar[node-1]=far;
      visited[node-1]=1;
    }

  for(int i=0;i<cols[node-1];i++)
    {
      //if(map[node-1][i]!=0)
	{
	  search(map[node-1][i], far+1);
	}
    }
  return -1;
}