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 <algorithm>
#include <iostream>
#include <queue>
#include <string>
using namespace std;
static const int MAX = 100;
int N;
int ADJ[MAX][MAX];
int depth[MAX];

enum STATUS { ACTIVE = 0, MARKED, VISITED, };
int status[MAX] = {ACTIVE};

void visit(int id) {
  status[id] = VISITED;
}
void mark(int id) {
  status[id] = MARKED;
}

void bfs(int id) {
  queue<int> q;
  q.push(id);
  depth[id] = 0;

  while (!q.empty()) {
    int u = q.front();
    q.pop();
    visit(u);
    for (int i = 0; i < N; i++) { 
      if (ADJ[u][i] && status[i] == ACTIVE) {
        q.push(i);
        mark(i);
        depth[i] = depth[u] + 1;
      }
    }
  }
}

int main() {
  cin >> N;
  int id, nn, x;
  for (int i = 0; i < N; i++) {
    cin >> id >> nn;
    id--; // 0-based
    for (int j = 0; j < nn; j++) {
      cin >> x;
      x--; // 0-based
      ADJ[id][x] = 1;
    }
  }
  for (int i = 0; i < N; i++)
    depth[i] = -1;

  bfs(0);
  for (int i = 0; i < N; i++)
    cout << i+1 << " " << depth[i] << endl;
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<cassert>
#include<cstdio>
#include<queue>
 
using namespace std;
 
int N, G[100][100], V[100], D[100];//G:２頂点,V:次数,D:距離
 
void bfs(int src){
    queue<int> Q;
    Q.push(src);
    fill(D, D + N, -1);
    D[src] = 0;
    while (! Q.empty()){
        int cur = Q.front();
        Q.pop();
        cerr << cur+1 << " " << D[cur] << endl;
        for (int k = 0; k < N; k++){
            if (G[cur][k] == 1 && D[k] == -1){
                D[k] = D[cur]+1;
                Q.push(k);
            }
        }
    }
}
 
int main(){
    scanf("%d", &N);
        int id, c;
        for (int i = 0; i < N; i++){
            scanf("%d", &id); id--;//配列は0から始まるので、頂点番号を-1して考える。
            scanf("%d", V + id);
            for (int j = 0; j < V[id]; j++){
                scanf("%d", &c); c--;//配列は0から始まるので、頂点番号を-1して考える。
                G[id][c] = 1;
            }
        }//データの読み込み完了。
    bfs(0);
   return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
vector<int> d;
vector<int> f;
vector<bool> used;
vector< vector<int> > v;
int n;
int cnt = 0;


int main(void){
  ios::sync_with_stdio(false);
  cin.tie(0);

  cin >> n;
  d = f = vector<int>(n, -1);
  used = vector<bool>(n, false);
  v = vector< vector<int> >(n, vector<int>(n, 0));
  for(int i = 0; i < n; i++){
    int u, k; cin >> u >> k;
    u--;
    for(int j = 0; j < k; j++){
      int a; cin >> a;
      a--;
      v[u][a] = 1;
    }
  }

  queue<int> que;
  que.push(0);
  d[0] = cnt;
  used[0] = true;
  while(!que.empty()){
    cnt++;
    int q = que.front(); que.pop();
    for(int i = 0; i < n; i++){
      if(v[q][i] && !used[i]){
        used[i] = true;
        que.push(i);
        d[i] = d[q]+1;
      }
    }
  }

  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 (int i = 0; i < n; i++)
#define rrep(i, n) for (int i = n - 1; i >= 0; i--)
using namespace std;
using Graph = vector<vector<int>>;
typedef long long ll;
typedef pair<long long,int> P;



int main(){
    int n;
    vector<int> g[105];
    cin >> n;
    rep(i, n){
        int a, b;
        cin >> a >> b;
        rep(j, b){
            int c;
            cin >> c;
            g[a].push_back(c);
        }
    }
    queue<int> que;
    int dist[105];
    rep(i, n + 1) dist[i] = -1;
    dist[1] = 0;
    que.push(1);

    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);
        }
    }

    rep(i, n) cout << i + 1 << " " << dist[i+1] << endl;

    return 0;
}

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

const int MAX_N = 100;

int main() {
    vector<int> G[MAX_N];
    int N; cin >> N;
    for(int i = 0; i < N; i++) {
        int u, k; cin >> u >> k; u--;
        while(k--) {
            int v; cin >> v; v--;
            G[u].push_back(v);
        }
    }

    vector<int> dist(N, -1);
    queue<int> Q;
    Q.push(0);
    dist[0] = 0;

    while(!Q.empty()) {
        int u = Q.front(); Q.pop();
        for(int i = 0; i < (int)G[u].size(); i++) {
            int v = G[u][i];
            if(dist[v] != -1) continue;
            dist[v] = dist[u] + 1;
            Q.push(v);
        }
    }
    for(int i = 0; i < N; i++) cout << i + 1 << ' ' << dist[i] << endl;
}

C++: #include <iostream>
#include <vector>
#include <queue>
using namespace std;
static const int MAX=101;

vector<int> Adjacency[MAX];
int dt[MAX];
bool Visited[MAX];

void bfs(int i)
{
    queue<int> Q;
    dt[i]=0;Q.push(i);
    Visited[i]=true;
    int d=0;
    while(!Q.empty())
    {
        int p=Q.front();Q.pop();d=dt[p]+1; //important
        for(int j=0;j<Adjacency[p].size();j++)
        {
            if(Visited[Adjacency[p][j]]==true) continue;
            //else
            Q.push(Adjacency[p][j]); Visited[Adjacency[p][j]]=true;
            dt[Adjacency[p][j]]=d;
        }
    }
}
int main()
{
    int n;
    cin>>n;
    for(int i=1;i<=n;i++) dt[i]=-1;
    for(int i=1;i<=n;i++)
    {
        int j,num;
        cin>>j>>num;
        for(int k=0;k<num;k++)
        {
            int t;cin>>t;
            Adjacency[j].push_back(t);
        }
    }
    bfs(1);
    for(int i=1;i<=n;i++)
    {
        cout<<i<<' '<<dt[i]<<endl;
    }
}