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 <vector>
#include <numeric>
#include <cassert>
#include <queue>

const int MAXINT = 1000000000;

void bfs(std::vector<std::vector<int> >& adj_list, std::vector<int>& d, int root = 0 ){
  std::queue<int> target_q;
  // std::queue<int> dist_q;
  target_q.push(root);
  d[root] = 0;
  // dist_q.push(0;)
  while(!target_q.empty()){
    int vtx = target_q.front(); target_q.pop();
    for(int const&  u : adj_list[vtx]){
      target_q.push(u);
      if(d[vtx] + 1 < d[u]){
        // std::cout<< "/* message */" << std::endl;
        d[u] = d[vtx] + 1;
      }
    }
  }
}


int main(int argc, char const *argv[]) {
  int n; // .. 100
  std::cin >> n;
  std::vector<std::vector<int> > adj_list(n);
  std::vector<int> d(n, MAXINT);

  for(int q=0; q<n; ++q){
    int i_plus_1, k;
    std::cin >> i_plus_1;
    std::cin >> k;
    for(int p=0; p<k; ++p){
      int j_plus_1;
      std::cin >> j_plus_1;
      // adj[i_plus_1-1][j_plus_1-1] = true;
      adj_list[i_plus_1 - 1].push_back(j_plus_1-1);
    }
  }
  bfs(adj_list, d, 0);

  for(int i=0; i<n; ++i){

    // if(d[i] < MAXINT){
      std::cout << (i+1)
        << " " << (d[i]==MAXINT ? -1 : d[i])
        << std::endl;
  }


  // for(auto it = adj_list.begin(); it != adj_list.end(); ++it){
  //   std::cout << ": ";
  //   for(auto jt = (*it).begin(); jt != (*it).end(); ++jt){
  //     std::cout << (*jt) << ' ';
  //   }
  //   std::cout << std::endl;
  // }

  return 0;
}

C++: #include<iostream>
#include<cstdio>
#define INF 1000000
#define NIL -2
#define GRAY -3
#define WHITE -4
#define BRACK -5

using namespace std;

int n;
int M[101][101];
int d[101];//重み
//int p[101];//親
int color[101];

void Dijkstra(int u) {
	//cout << u << endl;
	color[u] = BRACK;

	//重みの更新
	for (int i = 1; i <= n; i++) {
		if (color[i] != BRACK && M[u][i] != 0) {
			color[i] = GRAY;
			if ((d[u] + M[u][i]) < d[i]) {
				d[i] = d[u] + M[u][i];
			}
		}
		//cout << d[i] << " ";
	}

	//cout << endl;

	int min = -1;
	d[min] = 100000;


	for (int v = 1; v <= n; v++) {
		if (color[v] != BRACK) {
			if (d[v] < d[min]) {
				min = v;
			}
			else {
				color[v] = WHITE;
			}
		}
	}

	if (min != -1) {
		Dijkstra(min);
	}
}

int main() {
	cin >> n;
	int v, k, g, weight; //v = 節点番号　g = 次数

	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= n; j++) {
			M[i][j] = 0;
		}
	}

	for (int i = 1; i <= n; i++) {
		cin >> v >> g;
		for (int j = 1; j <= g; j++) {
			cin >> k;
			M[i][k] = 1;
		}
	}

	for (int i = 1; i <= n; i++) {
		color[i] = WHITE;
	}

	for (int i = 1; i <= n; i++) {
		d[i] = INF;
		//cout << d[i] << " ";
	}

	d[1] = 0;


	//関数
	Dijkstra(1);


	for (int i = 1; i <= n; i++) {
		if (d[i] == INF) {
			d[i] = -1;
		}
		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];

void bfs(int s)
{
	queue<int> q;
	q.push(s);
	for(int i=0;i<n;i++) d[i] = INF;
	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] != INF)continue;
			d[v] = d[u]+1;
			q.push(v);
		}
	}
	for(int i=0;i<n;i++){
		cout << i+1 << " " <<((d[i] == INF)?(-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<queue>
using namespace std;
const int MAX = 100;
int n, G[MAX + 1][MAX + 1];
bool book[MAX + 1] = { false };
int path[MAX + 1];
void breathFSearch(int orign)
{
	queue<int> Q;
	Q.push(orign);
	book[orign] = true;
	while (!Q.empty())
	{
		int u = Q.front();
		for (int v = 1; v <= n; v++)
		{
			if (G[u][v] && !book[v])
			{
				Q.push(v);
				book[v] = true;
				if(path[u]!=-1)
					path[v] = path[u]+1;
			}
		}
		Q.pop();
	}
}
int main()
{
	cin >> n;
	for (int i = 1; i <= n; i++)
	{
		int u, d;
		cin >> u >> d;
		for (int j = 1; j <= d; j++)
		{
			int v;
			cin >> v;
			G[u][v] = 1;
		}
	}
	for (int i = 1; i <= n; i++)
		path[i] = -1;
	path[1] = 0;
	for(int i=1;i<=n;i++)
		if(!book[i])
			breathFSearch(i);
	for (int i = 1; i <= n; i++)
		cout << i << " " << path[i] << endl;
}