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>

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>
using namespace std;

int main() {
	int a[101][101] = {{0}};
	int u, k, v, km;
	km = 0;
	while ( cin >> u, k ) {
		for ( int i = 1; i <= k; i++ ) {
			cin >> v;
			a[u][v] = 1;
		}
		km++;
	}
	int n0;
	int b[101] = {- 1};
	queue<int> q;
	q.push( 1 );
	b[1] = 0;
	int cou = 0;
	for ( int i = 1; i <= km; i++ ) {
		n0 = q.front();
		q.pop();
		cou++;
		for ( int j = 1; j <= km + 1; j++ ) {
			if ( a[n0][j] == 1 && b[j] == - 1 ) {
				q.push( j );
				b[j] = cou;
			}
			if ( q.empty() ) break;
		}
	}
	for ( int i = 1; i <= km; i++ )
		cout << i << " " << b[i] << endl;
}

C++: #include<cstdio>
#include<cstdlib>
#include<algorithm>
#include<iostream>
#include<queue>
#include<vector>
using namespace std;
#define MAX 100
#define WHITE 0
#define GRAY 1
#define BLACK 2



int d[MAX];
vector<int> V[MAX];
int tt=0;
queue<int> Q;

int main()  {
  int n;
  cin>>n;
  for(int i=0;i<n;i++){
    d[i]=-1;
  }

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

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

  while(!Q.empty()){
    v=Q.front(); Q.pop();
    for(int i=0;i<V[v].size();i++){
      if(d[V[v][i]]==-1) {
        Q.push(V[v][i]);
        d[V[v][i]]=d[v]+1;

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

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

using namespace std;

int n, M[100][100], d[100];

void bfs (int s) {

    int i, u, v;

    queue<int> Q;
    Q.push(s);
    for (i = 0; i < n; i++) {
        d[i] = (1 << 21);
    }
    d[s] = 0;
    while (!q.empty()) {
        u = Q.front();
        Q.pop();
        for (v = 0; v < n; v++) {
            if (M[u][v] == 0) {
                continue;
            }
            if (d[v] != (1 << 21)) {
                continue;
            }
            d[v] = d[u] + 1;
            q.push(v);
        }
    }
    for (i = 0; i < n; i++) {
        cout << i + 1 << " " << ((d[i] == (1 << 21)) ? (-1) : d[i]) << endl;
    }
}

int main () {

    int u, k, v, i, j;

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

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

    bfs (0);

    return 0;

}

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

bool A[110][110],flag[110];
int d[110];
int n;

void bfs(){
	queue<int> Q;
	Q.push(1);
	d[1]=0;
	while(Q.empty()==0){
		int u=Q.front();
		Q.pop();
		for(int i=2;i<=n;i++){
			if(A[u][i]==true && flag[i]==false ){
				flag[i]=true;
				Q.push(i);
				d[i]=d[u]+1;
			}
		}
	}
	for(int i=2;i<=n;i++) if(flag[i]==false) d[i]=-1;
	return ;
}

int main(){
	int a,b,c;
	cin>>n;
	for(int i=1;i<=n;i++){
		flag[i]=false;
			for(int j=1;j<=n;j++){
				A[i][j]=false;
		}
	}
	for(int i=1;i<=n;i++){
		cin>>a>>b;
		for(int j=1;j<=b;j++){
			cin>>c;
			A[a][c]=true;
		}
	}
	bfs();
	for(int i=1;i<=n;i++) cout<<i<<" "<<d[i]<<endl;	
	return 0;
}

C++: #include<iostream>
#include<climits>
#include<vector>
#include<list>
#include<functional>
#include<algorithm>
#include<string>
#include<cmath>
#include<complex>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<tuple>
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) for(int i=0;i<(n);i++)
#define INF (int)1e9
#define INFL (ll)1e11
using namespace std;
typedef long long ll;
typedef pair<int, int> P;

void bfs(vector<vector<int>> a, vector<int> &d) {
	int n = a.size();
	queue<int> qu;
	qu.push(0);
	while (!qu.empty()) {
		int i = qu.front();
		qu.pop();
		REP(j, n) {
			if (d[j] == -1 && a[i][j]) {
				d[j] = d[i] + 1;
				qu.push(j);
			}
		}
	}
}

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

	int n;
	cin >> n;
	vector<vector<int>> a(n, vector<int>(n, 0));
	REP(i, n) {
		int u, k;
		cin >> u >> k;
		u--;
		REP(j, k) {
			int v;
			cin >> v;
			a[u][--v] = 1;
		}
	}
	vector<int> d(n, -1);
	d[0] = 0;
	bfs(a, d);
	REP(i, n) {
		cout << i + 1 << " " << d[i] << "\n";
	}

	return 0;
}