Go: package main

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

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Scan()
	num, _ := strconv.Atoi(sc.Text())
	nodes := make(map[int]*node)

	for i := 0; i < num; i++ {
		sc.Scan()
		id, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		nodeNum, _ := strconv.Atoi(sc.Text())
		n := node{id, make([]int, 0), -1}
		for j := 0; j < nodeNum; j++ {
			sc.Scan()
			nid, _ := strconv.Atoi(sc.Text())
			n.nexts = append(n.nexts, nid)
		}
		nodes[id] = &n
	}
	nodes[1].depth = 0

	walk(1, 0, &nodes)
	for i := 1; i < len(nodes)+1; i++ {
		fmt.Printf("%v %v\n", (*nodes[i]).id, (*nodes[i]).depth)
	}
}

var time int
var record [100][100]bool
var q Queue

func walk(nid int, from int, nodes *map[int]*node) {
	q.Enqueue((*nodes)[nid])
	for !q.IsEmpty() {
		n := q.Dequeue().(*node)
		for _, v := range n.nexts {
			n2 := (*nodes)[v]
			if n2.depth != -1 {
				continue
			}
			n2.depth = n.depth + 1
			q.Enqueue((*nodes)[v])
		}
	}
}

type node struct {
	id    int
	nexts []int
	depth int
}

// Queue is Queue
type Queue struct {
	val []interface{}
}

// Enqueue value
func (queue *Queue) Enqueue(val interface{}) {
	queue.val = append(queue.val, val)
}

// Dequeue value
func (queue *Queue) Dequeue() interface{} {
	res := queue.val[0]
	queue.val = queue.val[1:len(queue.val)]
	return res
}

// IsEmpty return true when queue is empty
func (queue *Queue) IsEmpty() bool {
	return len(queue.val) == 0
}

C++: #include<iostream>
#include<cstdio>
#include<queue>
#define Lens 105
using namespace std;
int N;
int A[Lens][Lens];
int d[Lens];
char c[Lens];
queue<int> Q;

int main()
{
	cin >> N;
	Q.push(1);
	
	for (int i = 1; i <= N; i++)
	{
		int k, n;
		cin >> k >> n;
		c[k] = 'w';
		for (int i = 0; i < n; i++)
		{
			int j;
			cin >> j;
			A[k][j] = 1;
		}
	}
	c[1] = 'g';
	while (Q.size())
	{
		int i = Q.front();
		Q.pop();
		for(int j=1;j<=N;j++)
		{
			if (A[i][j] == 1 && c[j] == 'w')
			{
				c[j] = 'g';
				d[j] = d[i] + 1;
				Q.push(j);
			}	 
		}
	}
	for (int i = 2; i <= N; i++)
	{
		if (c[i] == 'w')
			d[i] = -1;
	}	
	for (int i = 1; i <= N; i++)
	{
		cout << i << ' ' << d[i] << endl;
	}
	return 0;
}

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

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

int n,M[N][N];
int d[N];
int v,i;
int u;
void bfs(int s){
  queue<int> q;
  q.push(s);
  for(i=0;i<n;i++)d[i]=INF;
  d[s]=0;
  while(!q.empty()){
    u=q.front();
    q.pop();
    for(v=0;v<n;v++){
      if(d[v]!=INF)continue;
      if(d[v]!=INF)continue;
      d[v]=d[u]+1;
      q.push(v);
    }
  }
  for(i=0;i<n;i++){
    cout << i+1 << " " << ((d[i]==INF) ? (-1) : d[i])<<endl;
  }
}
int main(){
  int u,k,v;
  int 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 <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 <iostream>
#include <utility>
#include <string>
#include <algorithm>
#include <set>
#include <queue>
#include <vector>
#define MAX 10010
#define rep(i,p) for(int i=0;i<p;i++)
#define pb push_back
using namespace std;
int n,hoge,foo;
int graph[MAX][MAX] = {0};
int D[MAX] = {-1};
void bfs (int src) {
  queue<int> Q;
  Q.push(src);
  rep(i,MAX) D[i] = -1;
  D[src] = 0;
  while (! Q.empty()) {
    int cur = Q.front();
    Q.pop();
    // cout << "visiting " << cur << " " << D[cur] << endl;
    for (int dst = 1; dst <= n; dst++) {
      if (graph[cur][dst] == 1 && D[dst] == -1) {
        D[dst] = D[cur] + 1;
        Q.push(dst);
      }
    }
  }
}
int main(){
  cin >> n;
  rep(i,n) {
    cin >> hoge >> foo;
    rep(j,foo) {
      cin >> hoge;
      graph[i+1][hoge] = 1;
    }
  }
  bfs(1);
  rep(i,n) cout << i+1 << " " << D[i+1] << endl;
  return 0;
}

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

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

int n,M[N][N];
//??????????????????????????¶??????color???
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=0;
    while(!q.empty()){
        u=q.front();q.pop();
        for(int v=0;v<n;v++)
            if(M[u][v]!=0&&d[v]==INFTY){
                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);
}