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>
#include<string>
#define NIL -1
using namespace std;
string color[101];//白色未访问，灰色访问，黑色退出队列
queue<int >BreathFirstSearch;//创建队列
int Distance[101];
int AM[101][101];
int total;
void includeInsertQueue(int i)
{
	for (int j = 0; j <= total; j++)
	{
		if (AM[i][j] && color[j] == "White")//存在且未被访问
		{
			color[j] = "Grey", Distance[j] =Distance[i]+1;//找到的点距离是其上一个再加一
			BreathFirstSearch.push(j);
		}
	}
}
void includeFirstSearch(int i)
{
	int next;
	BreathFirstSearch.push(i);//压入起点
	Distance[i] =0;//起点到起点的距离为0；
	color[i] = "Grey";
	while (!BreathFirstSearch.empty())
	{
		next = BreathFirstSearch.front();//队列头中取出元素
		BreathFirstSearch.pop();
		color[next] = "Black";
		includeInsertQueue(next);

	}
}
int main()
{	int TotalOfConnectedNode, node[101], connectednode;
	for (int i = 0; i < 101; i++) Distance[i]= NIL;
	for (int i = 0; i < 101; i++)color[i] = "White";
	for (int i = 0; i < 101; i++)
		for (int j = 0; j < 101; j++)
			AM[i][j] = 0;
	cin >> total;
	for (int i = 0; i < total; i++)//有向图
	{
		cin >> node[i] >> TotalOfConnectedNode;
		if (TotalOfConnectedNode == 0) continue;
		for (int j = 0; j < TotalOfConnectedNode; j++)
		{
			cin >> connectednode;
			AM[node[i]][connectednode] = 1;
		}
	}
	includeFirstSearch(node[0]);
	for (int i = 0; i < total; i++)
		cout << node[i] << " " << Distance[node[i]] << endl;

	
	return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < n; i++)
using namespace std;
using ll = long long;
using Graph = vector<vector<int>>;

int n;
Graph G;

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

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

const int nIMPOS = -1;
struct StDir
{
  int m_nx;
  int m_nEtc;

  StDir(int nx) : m_nx(nx), m_nEtc(0)
  { }
};

void fnInput(vector<vector<int>>& rvvnAdjcy, vector<int>& rvnDst)
{
  int nxSiz;
  cin >> nxSiz;

  rvvnAdjcy.resize(nxSiz + 1, vector<int>(nxSiz + 1, 0));
  for (int i = 0; i < nxSiz; ++i)
  {
    int nx, nySiz;
    cin >> nx >> nySiz;
    for (int j = 0; j < nySiz; ++j)
    {
      int ny;
      cin >> ny;
      rvvnAdjcy[nx][ny] = 1;
    }
  }
  rvnDst.resize(nxSiz + 1, nIMPOS);
}

void fnBreadthFirstSearch(const vector<vector<int>>& cnrvvnAdjcy, 
                          queue<StDir>& rqoBFSrch, vector<int>& rvnDst)
{
  while (rqoBFSrch.size())
  {
    StDir oDir = rqoBFSrch.front(); rqoBFSrch.pop();
    if (rvnDst[oDir.m_nx] == nIMPOS)  continue;

    for (int ny = 1; ny < cnrvvnAdjcy[oDir.m_nx].size(); ++ny)
      if (cnrvvnAdjcy[oDir.m_nx][ny] == 1)
      {
        int nDst = rvnDst[oDir.m_nx] + 1;
        if (rvnDst[ny] == nIMPOS)
          rvnDst[ny] = nDst;
        else
          rvnDst[ny] = min(rvnDst[ny], nDst);

        StDir oDir(ny);
        rqoBFSrch.push(oDir);
      }
  }
}

void fnResult(const vector<int>& cnrvnDst)
{
  for (int i = 1; i < cnrvnDst.size(); ++i)
    cout << i <<  " " << cnrvnDst[i] << endl;
}

int main()
{
  cin.tie(0);
  ios::sync_with_stdio(false);
  vector<vector<int>> vvnAdjcy;
  queue<StDir> qoBFSrch;
  vector<int>  vnDst;

  fnInput(vvnAdjcy, vnDst);

  vnDst[1] = 0;
  StDir oDir(1);
  qoBFSrch.push(oDir);
  fnBreadthFirstSearch(vvnAdjcy, qoBFSrch, vnDst);
  fnResult(vnDst);

  return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <climits>
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define repR(i, n) for(int i = (n) - 1; i > -1; i--)
#define rep1(i, n) for(int i = 1; i < (int)(n + 1); i++)
#define rep1R(i, n) for(int i = (n); i > 0; i--)
using namespace std;

static const int INFTY = INT_MAX;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int n;
int M[110][110] = {};
int color[110];
int d[110];
queue<int> Q;

void bfs(int s) {
  rep(u, n) color[u] = WHITE;
  rep(u, n) d[u] = INFTY;

  color[s] = GRAY;
  d[s] = 0;
  Q.push(s);

  while (!Q.empty()) {
    int u = Q.front(); Q.pop();
    rep(v, n) {
      if (M[u][v] && color[v] == WHITE) {
        color[v] = GRAY;
        d[v] = d[u] + 1;
        Q.push(v);
      }
    }
    color[u] = BLACK;
  }
}

int main() {
  cin >> n;
  rep(i, n) {
    int id, deg;
    cin >> id >> deg;
    --id;    // 0-indexedに直す
    rep(j, deg) {
      int v;
      cin >> v;
      --v;    // 0-indexedに直す
      ++M[id][v];
    }
  }
  bfs(0);
  rep(i, n) {
    cout << i + 1 << " ";
    if (d[i] != INFTY) cout << d[i];
    else cout << -1;
    cout << endl;
  }
  return 0;
}