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 <bits/stdc++.h>

using namespace std;

#define REP(i, n) for(int i = 0; i < n; i++)

int M[100][100];
int d[100];
int n;
static const int INFTY = (1 << 21);

void bfs(int x) {
    queue<int> q;
    q.push(x);
    REP (i, n) d[i] = INFTY;

    d[x] = 0;
    while (!q.empty()) {
        int u;
        u = q.front();
        q.pop();
        REP(i, n) {
            if (M[u][i] == 0) continue;
            if (d[i] != INFTY) continue;
            d[i] = d[u] + 1;
            q.push(i);
        }
    }

    REP(i, n) {
        cout << i + 1 << " ";
        if (d[i] == INFTY) {
            cout << -1 << endl;
        } else {
            cout << d[i] << endl;
        }
    }
}

int main() {
    cin >> n;
    int v, m, k;
    REP(i, n) {
        cin >> v >> m;
        v--;
        REP(j, m) {
            cin >> k;
            k--;
            M[v][k] = 1;
        }
    }

    bfs(0);
    return 0;
}

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

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

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

coid dfs(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 =.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 <vector>
#include <queue>

int main()
{
	int n;
	std::cin >> n;
	std::vector<std::vector<int> > E(n); 
	for (int i = 0; i < n; i++)
	{
		int u, k;
		std::vector<int> G;
		std::cin >> u >> k;
		u--;
		for (int j = 0; j < k; j++)
		{
			int g;
			std::cin >> g;
			g--;
			G.push_back(g);
		}
		E.at(u) = G;
	}
	std::vector<int> Dist(n, -1);
	Dist.at(0) = 0;
	std::queue<int> Que;
	Que.push(0);
	while (!(Que.empty()))
	{
		int s = Que.front();
		Que.pop();
		for (int i = 0; i < E.at(s).size(); i++)
		{
			int next = E.at(s).at(i);
			if (Dist.at(next) == -1)
			{
				Dist.at(next) = Dist.at(s) + 1;
				Que.push(next);
			}
		}
	}
	for (int i = 0; i < n; i++)
		std::cout << i + 1 << ' ' << Dist.at(i) << '\n';
	return 0;
}

C++: #include <iostream>
#include <queue>
#include <cstdlib>
int INF = 1e9;
int main(){
    long long n;
    std::cin >> n;
    std::vector<int> G[n];
    std::vector<int> used(n, 0);
    for(int i = 0; i < n; i++){
        int a, k;
        std::cin >> a >> k;
        a--;
        for(int j = 0; j < k; j++){
            int b;
            std::cin >> b;
            b--;
            G[a].push_back(b);
        }
    }
    std::vector<int> d(n, INF);
    std::queue<int> q;
    q.push(0);
    d[0] =0;
    while(!q.empty()){
        int t = q.front();
        q.pop();
        used[t] = 1;
        for(int i: G[t]){
            if(used[i] == 0){
                q.push(i);
                d[i] = std::min(d[i], d[t] + 1);
            }
        }
    }
    for(int i = 0; i < n; i++) if(d[i] == INF) d[i] = -1;
    for(int i = 0; i < n; i++) std::cout << i + 1 << ' ' << d[i] <<  std::endl;
}

C++: #include<iostream>
using namespace std;
int n, u,k[101], v[101][101], out[101];

void hitung(int a, int b){
	int i;
	out[a]=b;
	for(i=1; i<=k[a]; i++){
		if(out[v[a][i]]==-1 || out[v[a][i]]>b+1){
			hitung(v[a][i],	b+1);
		}
	}
}

int main(){
	int i,j;
    cin>>n;
    for(i=1; i<=n; i++){
        cin>>u>>k[i]; //getchar();
		out[i]=-1;
        for(j=1; j<=k[i]; j++){
            cin>>v[i][j];// getchar();
        }
    }
    
    hitung(1,0);
	for(i=1;i<=n;i++){
		cout<<i<<" "<<out[i]<<endl;
	}


    //getchar();
    return 0;
}

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

const int maxn=(1<<21);
int G[110][110];///构造图
int d[110];///该顶点到顶点1的距离
bool vis[110];
int n;

void BFS(){
    queue<int> q;
    q.push(1);
    d[1]=0;
    vis[1]=true;
    while(!q.empty()){
        int top=q.front();
        q.pop();
        //vis[top]=true;
        for(int i=1;i<=n;i++){
            if(G[top][i]&&vis[i]==false){
       //     if(G[top][i]&&d[i]==maxn){
                d[i]=d[top]+1;
                vis[i]=true;
                q.push(i);
            }
        }
    }
}


int main(){
    scanf("%d",&n);
    memset(G,0,sizeof(G));
    memset(vis,0,sizeof(vis));
    fill(d,d+110,maxn);

  //  memset(d,maxn,sizeof(d));
    for(int i=0;i<n;i++){
        int u,k;
        scanf("%d%d",&u,&k);
        for(int j=0;j<k;j++){
            int v;
            scanf("%d",&v);
            G[u][v]=1;
        }
    }

    BFS();
    for(int i=1;i<=n;i++){
        printf("%d %d\n",i,(d[i]==maxn)?(-1):d[i]);
    }
    return 0;
}