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<queue>
#define N 100
#define NIL -1

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

// 初期化処理後、sを開始地点として幅優先探索を行い、探索結果を出力する
// d[N]にはsからの距離を記録し(sは0)、sからたどり着けない頂点はNIL(空)を記録する
void bfs(int s)
{
	for (int i = 0; i < n; i++)d[i] = NIL;

	std::queue<int> Q;
	Q.push(s);
	d[s] = 0;

	while (!Q.empty())
	{
		int u = Q.front();
		Q.pop();
		for (int v = 0; v < n; v++)
		{
			if (M[u][v] == 0)continue;
			if (d[v] != NIL) continue;
			Q.push(v);
			d[v] = d[u] + 1;
		}
	}

	for (int i = 0; i < n; i++)
	{
		std::cout << i + 1 << " " << d[i] << std::endl;
	}
}

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

	int u, v, k;
	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);
}

C++: #include<cstdio>
#include<algorithm>
#include<queue>
#include<vector>
#include<map>
using namespace std;
typedef pair< int, int > Pi;
const int INF = 1 << 30;
struct edge: vector< Pi > {
  void add_edge(int to, int cost){
    push_back(Pi(to,cost));
  }
} info[100000];
int hoge[100000];
 
void bfs(const int& st, const int& V){
  fill_n( hoge, V, INF);
  queue< int > que;
  que.push(st);
  hoge[st] = 0;
  while(!que.empty()){
    int p = que.front();
    que.pop();
    for(int i = 0 ; i < info[p].size() ; i++){
      int cost = info[p][i].second;
      int to = info[p][i].first;
      if( cost + hoge[p] < hoge[to]){
        que.push(to);
        hoge[to] = cost + hoge[p];
      }
    }
  }
}
 
int main(){
  int N;
  scanf("%d", &N);
  for(int i = 0; i < N; i++){
    int u, k;
    scanf("%d %d", &u, &k);
    u--;
    while(k--){
      int v;
      scanf("%d", &v);
      info[u].add_edge( v - 1, 1);
    }
  }
  bfs(0, N);
  for(int i = 0 ; i < N ; i++ ){
    printf("%d %d\n", i + 1, hoge[i]==INF?-1:hoge[i]);
  }
}

C++: #include <map>
#include <set>
#include <list>
#include <cmath>
#include <queue>
#include <stack>
#include <cstdio>
#include <string>
#include <vector>
#include <complex>
#include <cstdlib>
#include <cstring>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <functional>
 
#define mp       make_pair
#define pb       push_back
#define all(x)   (x).begin(),(x).end()
#define rep(i,n) for(int i=0;i<(n);i++)
 
using namespace std;
 
typedef    long long          ll;
typedef    unsigned long long ull;
typedef    vector<bool>       vb;
typedef    vector<int>        vi;
typedef    vector<vb>         vvb;
typedef    vector<vi>         vvi;
typedef    pair<int,int>      pii;
 
const int INF=1<<29;
const double EPS=1e-9;
 
const int dx[]={1,0,-1,0},dy[]={0,-1,0,1};

std::vector<vector<int> > G;
std::vector<int> flag;
std::vector<int> in;
int N;
typedef pii P;

int main(int argc, char const *argv[]) {
	
	cin >> N;

	for (int i = 0; i < N; ++i) {
		G.push_back(vector<int>());
		flag.push_back(0);
		in.push_back(-1);
		for (int j = 0; j < N; ++j) {
			G[i].push_back(0);
		}
	}

	for (int i = 0; i < N; ++i) {
		int u, k;
		cin >> u >> k;
		u--;
		for (int j = 0; j < k; ++j) {
			int v;
			cin >> v;
			v--;
			G[u][v] = 1;
		}
	}
	queue<P> q;
	q.push(mp(0, 0));
	while(!q.empty()) {
		P u = q.front(); q.pop();
		int dist = u.second;
		in[u.first] = dist;
		for (int i = 0; i < N; ++i) {
			if (flag[i] == 0 && G[u.first][i] == 1) {
				q.push(mp(i, dist + 1));
				flag[i] = 1;
			}
		}
	}

	for (int i = 0; i < N; ++i) {
		cout << i + 1 << " " << in[i] << endl;
	}

	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)
      {
        // 繋がってない
        continue;
      }
      if (d[v] != INFTY)
      {
        // 訪問済
        continue;
      }
      d[v] = d[u] + 1; // 一つ先
      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;
}