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>
using namespace std;

int main(){
  queue<int> q;
  int n,k,u,max=0;
  int g[101]={},f[101];
  int d[101][101]={};
  int di;
  cin>>n;
  for(int i=0;i<101;i++) f[i]=-1;
  f[1]=0;
  g[1]=1;
  for(int i=0;i<n;i++){
    cin>>u>>k;
    if(max<k) max=k;
    for(int j=0;j<k;j++){
      cin>>di;
      if(g[di]==0){
	g[di]=1;
	d[u][j]=di;
      }
    }
  }

  q.push(1);

  int cnt=1,fg;
  int a;
  while(!q.empty()){
    fg=0;
 a=q.front();
    for(int i=0;i<=max;i++){

      if( d[a][i]>0){
	fg=1;
	q.push(d[a][i]);
	f[d[a][i]]=cnt;
      }
    }
      q.pop();
    if(fg==1) cnt++;
  }
  for(int i=1;i<=n;i++) cout<<i<<" "<<f[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] == 1 && d[v] == INF) {
				d[v] = d[u] + 1;
				q.push(v);
			}
		}
	}
	for (int i = 0; i < n; i++) {
		cout << i+1 << " " << d[i] << endl;
	}
}
int main(int argc, char *argv[]) {
	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 <string>
#include <vector>
#include <queue>

using namespace std;

template<typename ISTREAM>
void readGraphList(ISTREAM& cin, vector< vector<int> >& graphList) {
	size_t n;
	cin >> n;
	graphList = vector< vector<int> >(n);
	for (size_t i = 0; i != n; ++i) {
		size_t u;
		size_t k;
		cin >> u;
		cin >> k;
		vector<int>& v = graphList.at(u - 1);
		v.resize(k);
		for (size_t j = 0; j != k; ++j) {
			cin >> v.at(j);
			v.at(j)--;
		}
	}
}
#if 1
void widthSearch(const vector<vector<int>>& graphList) {
	const size_t n = graphList.size();
	queue<int> nodeQueue;
	vector<int> distanceList(n, -1);
	distanceList.front() = 0;
	nodeQueue.push(0);
	while (!nodeQueue.empty()) {
		const int id = nodeQueue.front();
		const int distanceOfNextNode = distanceList.at(id) + 1;
		const vector<int>& adjList = graphList.at(id);
		for (const auto& adjID : adjList) {
			int& nextNodeDistance = distanceList.at(adjID);
			if (nextNodeDistance != -1)continue;
			nodeQueue.push(adjID);
			nextNodeDistance = distanceOfNextNode;
		}
		nodeQueue.pop();
	}
	for (int i = 0; i != n; ++i) {
		cout << i + 1 << " " << distanceList.at(i) << endl;
	}
}
#endif

template<typename T>
void execute(T& cin) {
	vector< vector<int> > graphList;
	readGraphList(cin, graphList);
	widthSearch(graphList);
}

int main()
{
	execute(cin);

	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 P = pair<int, int>;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
*/

int to[105][105];

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n;
    cin >> n;
    vector<vector<int> > G(n);
    rep(i,n){
        int u, k;
        cin >> u >> k;
        u--;
        rep(j,k){
            int v;
            cin >> v;
            v--;
            to[u][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();
        rep(nv,n){
            if(!to[v][nv]) continue;
            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<queue>

using namespace std;
#define MAX 100

const int INF = (1<<21);
int mat[MAX][MAX] = {};
int n, d[MAX] = {};
bool c[MAX];

void bfs(int u){
    queue<int> p; 
    int now = 0;
    d[u] = now++;
    c[u] = true;

    p.push(u);
    while(!p.empty()){
        int x = p.front(); p.pop();
        for(int i = 0; i < n; i++){
            if(mat[x][i] && !c[i]){
                p.push(i);
                c[i] = true;
                d[i] = d[x]+1;
            }
        }
    }
}

int main(){
    cin >> n;
    
    for(int i = 0; i < n; i++){
        int x, k, y;
        cin >> x >> k;
        while(k-- > 0){
            cin >> y;
            mat[x-1][y-1] = 1;
        }
    }

    for(int i = 0; i < n; i++) d[i] = INF;
    
    bfs(0);

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