Go: package main

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

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)
	nodes := make([]Node, n)

	for i := 0; i < n; i++ {
		nodes[i].list = make([]int, 0)
		nodes[i].d = -1
	}

	for i := 0; i < n; i++ {
		u := getNextInt(scanner)
		k := getNextInt(scanner)
		u--
		for ii := 0; ii < k; ii++ {
			v := getNextInt(scanner)
			v--
			nodes[u].list = append(nodes[u].list, v)
		}
	}

	queue := make([]int, n)
	queue[0] = 0
	nodes[0].d = 0
	d := 0
	i, j := 0, 1
	for i < j {
		d++
		prev := j
		for i < prev {
			for k, l := 0, len(nodes[queue[i]].list); k < l && i < n; k++ {
				if nodes[nodes[queue[i]].list[k]].d != -1 {
					continue
				}
				nodes[nodes[queue[i]].list[k]].d = d
				queue[j] = nodes[queue[i]].list[k]
				j++
			}
			i++
		}
	}

	for i := 0; i < n; i++ {
		fmt.Fprintln(writer, fmt.Sprintf("%d %d", i+1, nodes[i].d))
	}

	writer.Flush()
}

// Node ...
type Node struct {
	list []int
	d    int
}

C++: #include <bits/stdc++.h>
#define REP(i,n) for (int i = 0; i <(n); ++i)
#define REP2(i,x,n) for (int i = x; i <(n); ++i)
#define ALL(v) v.begin(), v.end()
#define RALL(v) v.rbegin(), v.rend()
using namespace std;
using ll = long long;
using P = pair<int,int>;
static const double PI = acos(-1);

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

int d[N]; //距離で訪問状態を管理する
int n, M[N][N];

void bfs(int s){
  queue<int> q;
  q.push(s);

  REP(i,n) d[i] = INF;

  d[s] = 0;
  int u;
  while(!q.empty()){
    u = q.front(); q.pop();
    REP(v,n){
      //つながっていなかったら，飛ばす
      if(M[u][v] == 0) continue;
      //既に訪れていたら，飛ばす
      if(d[v] != INF) continue;

      d[v] = d[u] + 1;
      q.push(v);
    }
  }

  REP(i,n){
    cout << i + 1 << " " << ((d[i] == INF) ? (-1) : d[i] ) << endl;
  }




}
int main(){
  int u, k, v;
  cin >> n;
  REP(i,n){
    REP(j,n) M[i][j] = 0;
  }

  REP(i,n){
    cin >> u >> k;
    --u;
    REP(i,k){
      cin >> v;
      --v;
      M[u][v] = 1;
    }
  }

  bfs(0);
  return 0;
}

C++: 
//push(),pop():C++ではstackと統一されいる
//front():先頭の要素が何かを返す
//back():末尾の要素が何であるかを返す
//empty():キューが空であるかどうかを調べる
//size():要素数を調べる
#include<stdio.h>
#include <iostream>
#include <queue>
using namespace std;
#define MAX 101
#define WHITE 0
#define GRAY 1
#define BLACK 2
static const int INFTY = (1<<21);

int G[MAX][MAX],color[MAX],d[MAX],num;

void bfs(int s){
  int u;
  queue<int> Q; //Qを使うことでエンキュー、デキューの操作が容易になる
  for(int i=1; i<=num; i++) {
    d[i] = INFTY;
  }
  Q.push(s);
  d[s] = 0;
  while(!Q.empty()){
    u = Q.front();
    Q.pop();
    for(int v=1; v<=num; v++){
      if(G[u][v] == 0) continue;
      if(d[v] != INFTY) continue;
      d[v] = d[u] + 1;
      Q.push(v);
    }
  }
}


int main(){
  int i,j,u,k,v;

  scanf("%d",&num);
  for(i=1; i<=num; i++){
    color[i] = WHITE;
    for(j=1; j<=num; j++){
      G[i][j] = 0;
    }
  }
  for(i=1; i<=num; i++){
    scanf("%d%d",&u,&k);
    for(j=1; j<=k; j++){
      scanf("%d",&v);
      G[u][v] = 1;
    }
  }

  bfs(1);

  for(i=1; i<=num; i++) {
    if(d[i] == INFTY) printf("%d -1\n",i);
    else printf("%d %d\n",i,d[i]);
  }

  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

#define MAX 100
#define WHITE 0
#define GRAY 1
#define BLACK 2

int n;
bool G[MAX + 1][MAX + 1];
int col[MAX + 1];
int d[MAX + 1];

void init(int n) {
	for (int i = 1; i <= n; i++) {
		col[i] = WHITE;
		d[i] = -1;
		for (int j = 1; j <= n; j++)
			G[i][j] = 0;
	}
}

void bfs(int u) {
	queue<int> Q;
	Q.push(u);
	col[u] = GRAY;
	d[u] = 0;
	while (!Q.empty()) {
		int v = Q.front();
		Q.pop();
		for (int i = 1; i <= n; i++) {
			if (G[v][i] && col[i] == WHITE) {
				Q.push(i);
				col[i] = GRAY;
				d[i] = d[v] + 1;
			}
		}
		col[v] = BLACK;
	}
}

int main() {
	cin >> n;
	init(n);
	for (int i = 0; i < n; i++) {
		int u, k;
		cin >> u >> k;
		for (int j = 0; j < k; j++) {
			int v;
			cin >> v;
			G[u][v] = 1;
		}
	}
	bfs(1);
	for (int u = 1; u <= n; u++) {
		cout << u << " " << d[u] << endl;
	}
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;


int main(){
  int n;
  cin >> n;
  vector<vector<int>> g(n);
  for(int i=0;i<n;++i){
    int id,k;
    cin >> id >> k;
    id--;
    for(int j=0;j<k;++j){
      int v;
      cin >> v;
      v--;
      g[id].push_back(v);
    }
  }
  vector<int> dist(n,-1);
  queue<int> que;
  dist[0]=0;
  que.push(0);
  while(!que.empty()){
    int v=que.front();
    que.pop();
    for(auto nv : g[v]){
      if(dist[nv]!=-1)continue;
      dist[nv]=dist[v]+1;
      que.push(nv);
    }
  }
  for(int i=0;i<n;++i){
    cout << i+1 << " " << dist[i] << endl;
  }
  return 0;
}

C++: #include <iostream>
#include <queue> 
using namespace std;
int G[100][100];
int d[100];
int color[100];
int n;
queue<int> qu;
void bfs ()
{
    color[0] = 1;
    d[0] = 0;
    qu.push(0);
    while (!qu.empty())
    { 
        int u = qu.front(); qu.pop();
        for (int i = 0; i < n; i++)
        {
            if (G[u][i] == 1 && color[i] == 0)
            {
                color[i] = 1;
                d[i] = d[u] + 1;
                qu.push(i);
            }
        }
        color[u] = 2;
    } 
    return;
}

int main()
{
    int k, u, v;
    cin>>n;
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < n; j++)
        {
            G[i][j] = 0; 
        }  
    } 

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

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

C++: #include<bits/stdc++.h>
#define REP(i,n) for(long long i=0;i<n;++i)
#define FOR(i,a,b) for(long long i=a;i<b;++i)
using namespace std;
const int INF=1<<30;
int n,graph[101][101],v[101];
void bfs(int s){
    queue< int > q;
    fill(v,v+101,INF);
    q.push(s);
    v[s]=0;
    while(!q.empty()){
        int p=q.front();q.pop();
        FOR(i,1,n+1){
            if(!graph[p][i]) continue;
            if(v[i]==INF){
                v[i]=v[p]+1;
                q.push(i);
            }
        }
    }
    FOR(i,1,n+1){
        printf("%d ",i);
        printf("%d\n",v[i]!=INF?v[i]:-1);
    }
}
int main(){
    int u,k,e;
    scanf("%d",&n);
    REP(i,n){
        scanf("%d%d",&u,&k);
        REP(j,k){
            scanf("%d",&e);
            graph[u][e]=1;
        }
    }
    bfs(1);
    return 0;
}