Go: package main

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

//util
var sc = bufio.NewScanner(os.Stdin)

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

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func printList(list []int) {
	n := len(list)
	buf := bufio.NewWriter(os.Stdout)
	for _, v := range list[0 : n-1] {
		buf.Write([]byte(fmt.Sprintf("%d ", v)))
	}
	buf.Write([]byte(fmt.Sprintf("%d\n", list[n-1])))
	buf.Flush()
}

func max(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func min(a, b int) int {
	if a > b {
		return b
	} else {
		return a
	}
}

//solve
const INFTY = (1 << 21)
const MAX = 100
const WHITE = 0
const GRAY = 1
const BLACK = 2

var time, n int

//隣接行列
var M [MAX][MAX]int

//d[i]: 頂点1から頂点iまでの距離
var color, d [MAX]int

func bfs(s int) {
	var q []int
	q = append(q, s)
	for i := 0; i < n; i++ {
		d[i] = INFTY
	}
	//sは開始点なので、0をいれる
	d[s] = 0

	//キューが空になるまで、以下を繰り返す
	for len(q) > 0 {
		u := q[0]
		q = q[1:]
		for v := 0; v < n; v++ {
			if M[u][v] == 0 {
				continue
			}
			if d[v] != INFTY {
				continue
			}
			d[v] = d[u] + 1
			q = append(q, v)
		}
	}

	for i := 0; i < n; i++ {
		fmt.Printf("%d ", i+1)
		if d[i] == INFTY {
			fmt.Printf("%d\n", -1)
		} else {
			fmt.Printf("%d\n", d[i])
		}
	}
}

func main() {
	sc.Split(bufio.ScanWords)
	n = nextInt()
	for i := 0; i < n; i++ {
		u, k := nextInt(), nextInt()
		M[u-1][u-1] = 0

		//fmt.Println(u, k)
		if k > 0 {
			for j := 0; j < k; j++ {

				v := nextInt()
				M[u-1][v-1] = 1

			}
		}

	}

	bfs(0)

}

C++: #include <algorithm>
#include <complex>
#include <cstdlib>
#include <ctime>
#include <iomanip>
#include <iostream>
#include <map>
#include <math.h>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>

using namespace std;
#define SAY_YES cout << "YES" << endl;
#define SAY_Yes cout << "Yes" << endl;
#define SAY_NO cout << "NO" << endl;
#define SAY_No cout << "No" << endl;
#define IFYES(TRUE_OR_FALSE)   \
    if (TRUE_OR_FALSE)         \
    {                          \
        cout << "YES" << endl; \
    }                          \
    else                       \
    {                          \
        cout << "NO" << endl;  \
    }
#define IFYes(TRUE_OR_FALSE)   \
    if (TRUE_OR_FALSE)         \
    {                          \
        cout << "Yes" << endl; \
    }                          \
    else                       \
    {                          \
        cout << "No" << endl;  \
    }
#define IFyes(TRUE_OR_FALSE)   \
    if (TRUE_OR_FALSE)         \
    {                          \
        cout << "yes" << endl; \
    }                          \
    else                       \
    {                          \
        cout << "no" << endl;  \
    }
#define DEBUG_OUTPUT_ARRAY(XXX, ONE)                            \
    for (int i = 0; i < (ONE); i++)                             \
    {                                                           \
        cout << "DEBUG: i = " << i << " -> " << XXX[i] << endl; \
    }
#define DEBUG_OUTPUT_ARRAY2(XXX, ONE, TWO)                             \
    for (int i = 0; i < (ONE); i++)                                    \
    {                                                                  \
        cout << "<<< i = " << i << " >>>" << endl;                     \
        for (int j = 0; j < (TWO); j++)                                \
        {                                                              \
            cout << "DEBUG: j = " << j << " -> " << XXX[i][j] << endl; \
        }                                                              \
    }
#define DEBUG_OUTPUT_ARRAY2_BOX(XXX, ONE, TWO) \
    for (int i = 0; i < (ONE); i++)            \
    {                                          \
        cout << i << "  ";                     \
        for (int j = 0; j < (TWO); j++)        \
        {                                      \
            cout << XXX[i][j] << " ";          \
        }                                      \
        cout << endl;                          \
    }

typedef pair<long long int, long long int> pll;


const long long int mod = 1000000007;
const long long int INF = 99999999999999999;

long long int n,u[105],k[105],v[105][105],used[105]={},num[105]={};
vector<long long int>vec[200];
queue<long long int>que;
int main()
{
    cout << fixed << setprecision(18);
	cin>>n;
	for(int i=0;i<n;i++){
		cin>>u[i]>>k[i];
		u[i]--;
		for(int j=0;j<k[i];j++){
			cin>>v[i][j];
			v[i][j]--;
			vec[u[i]].push_back(v[i][j]);
		}
	}
	que.push(0);
	
	for(int i=0;i<n;i++){
		num[i]=-1;
	}
	num[0]=0;
	used[0]=true;
	while(!que.empty()){
		
		used[que.front()]=true;
		for(int i=0;i<vec[que.front()].size();i++){
			if(!used[vec[que.front()][i]]){que.push(vec[que.front()][i]);
			num[vec[que.front()][i]]=num[que.front()]+1;used[vec[que.front()][i]]=true;}			
		}
		que.pop();
	}
	
	for(int i=0;i<n;i++){
		cout<<i+1<<" "<<num[i]<<endl;
	}
}

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];  //距離で訪問状態(color)を管理する

void bfs(int s){
  queue<int> q;  //標準ライブラリを使用する(テストでは使用×)
  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++){
    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<cstdio>
#include<queue>
using namespace std;

int main()
{
	int i,j,n,k,e[101][101],v[101],a,b,d[101],s;
	queue<int> Q;
	
	for(i=0;i<=100;i++)
	{
		for(j=0;j<=100;j++)
		{
			e[i][j]=0;
		}
		v[i]=0;
		d[i]=-1;
	}
	scanf("%d",&n);
	for(i=0;i<=n-1;i++)
	{
		scanf("%d%d",&a,&k);
		for(j=0;j<=k-1;j++)
		{
			scanf("%d",&b);
			e[a][b]=1;
		}
	}
	
	Q.push(1);
	d[1]=0;
	s=1;
	v[1]=1;
	while(Q.empty()!=1)
	{
		i=Q.front();
		for(j=1;j<=n;j++)
		{
			if(e[i][j]==1 && v[j]==0)
			{
				d[j]=d[i]+1;
				v[j]=1;
				Q.push(j);
			}
		}
		Q.pop();
	}
	for(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;
void bfs(int);
int n,M[N][N],d[N],u,i,j;
string color[N];
int main(){
  int inu,k,v;
  cin >> n;
  for(i=1;i<=n;i++){
    for(j=1;j<=n;j++){
      M[i][j]=0;
    }
  }
  for(i=1;i<=n;i++){
    cin >> inu >> k;
    for(j=0;j<k;j++){
      cin >> v;
      M[inu][v]=M[v][inu]=1;
    }
  }
  bfs(1);
  for(i=1;i<=n;i++){
    if(d[i]>n) cout << i << ' ' << -1 << endl;
    else cout << i << ' ' << d[i] << endl;
  }
  return 0;
}
void bfs(int s){
  queue<int> q;
  for(i=1;i<=n;i++){
    color[i]="WHITE";
    d[i]=1000000000;
  }
  color[s]="GLAY";
  d[s]=0;
  q.push(s);
  while(q.empty()!=true){
    u=q.front();
    q.pop();
    for(i=1;i<=n;i++){
      if(M[u][i]&&color[i]=="WHITE"){
	color[i]="GLAY";
	d[i]=d[u]+1;
	q.push(i);
      }
    }
    color[u]="BLACK";
  }
}