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>
/*
#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <cstring>
#include <complex>
#include <stack>
#include <queue>
#include <unordered_map>
#include <map>
*/
#define rep(i, a) for (int i = 0; i < (a); i++)
using namespace std;

int main(){
    int n;
    cin >> n;
    int g[110][110];
    int i, j;
    int u, k, v;
    pair<int, int> p;
    int dist[110];
    bool visited[110];
     
    for(i = 0; i < n; i++){
        for(j = 0; j < n; j++){
            g[i][j] = 0;
        }
    }
     
    for(i = 0; i < n; i++){
        dist[i] = -1;
        visited[i] = false;
    }
     
    for(i = 0; i < n; i++){
        cin >> u >> k;
        u--;
        for(j = 0; j < k; j++){
            cin >> v;
            v--;
            g[u][v] = 1;
        }
    }

	queue< pair<int, int> > q;
	for(i = 0; i < n; i++){
		if(g[0][i]) q.push(make_pair(0, i));
	}

	dist[0] = 0;
	visited[0] = true;
	while(!q.empty()){
		p = q.front();
		q.pop();

		if(visited[p.second]) continue;
		visited[p.second] = true;

		dist[p.second] = dist[p.first] + 1;

		for(j = 0; j < n; j++){
            if(g[p.second][j]){
                q.push(make_pair(p.second, j));
            }
        }
	}

	for(i = 0; i < n; i++){
        printf("%d %d\n", i+1, dist[i]);
    }
}

C++: #include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <map>
#include <numeric>
#include <string>
#include <cmath>
#include <iomanip>
#include <string>
#include <queue>
#include <list>
#include <stack>

typedef long long ll;
using namespace std;
const int mod = 1000000007;

void bfs(int node);
vector< vector<int> > Adj(100, vector<int>(100));
vector<int> dist(100, -1);
int n;

int main() {

    // input
    cin >> n;
    for (int i = 0; i < n; i++) {
        int u, k; cin >> u >> k;
        for (int j = 0; j < k; j++) {
            int v; cin >> v; v--;
            Adj[i].push_back(v);
        }
    }

    dist[0] = 0;
    bfs(0);

    for (int i = 0; i < n; i++) {
        cout << i + 1 << ' ' << dist[i] << '\n';
    }

}

void bfs(int node) {

    queue<int> q;
    q.push(node);

    while (!q.empty()) {
        int cur = q.front();
        q.pop();
        for (int i = 0; i < Adj[cur].size(); i++) {
            int v = Adj[cur][i];
            // visited
            if (dist[v] != -1) {
                continue;
            }
            // not visited
            else {
                dist[v] = dist[cur] + 1;
                q.push(v);
            }
        }
    }

}

C++: #include <iostream>
#include <queue>
#define INFTY -1
using namespace std;



int a[124][124] = {{}};
int d[124] = {};
int n;
void bfs(int k){
  queue <int> q;
  q.push(k);
  int u;


  while(!q.empty()){
    u = q.front(); q.pop();
    for(int v = 0;v < n;v++){
      if(a[u][v] == 0) continue;
      if(d[v] == INFTY) {
        d[v] = d[u] + 1;
        q.push(v);
        cout << v << " " << d[v] << endl;
      }
    }

  }
}

int main(){

  int u,k,x;
  cin >> n;

d[0] = 0;
for(int i = 1; i < n;i++) d[i] = INFTY;

  for(int i = 0;i < n;i++){
    cin >> u >> k;
    for(int j = 0;j < k;j++){
      cin >> x;
      a[u - 1][x - 1] = 1;
    }
  }

  bfs(0);

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

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

void calc(const vector<vector<int> >& G, vector<int>& D,
                                        queue<int>& Q, int dim) {
    if (Q.empty()) return;
    queue<int> Q2;
    while (!Q.empty()) {
        int i = Q.front();
        for (int j = 1; j < G[i].size(); j++) {
            if (G[i][j] && D[j] == -1) {
                Q2.push(j);
                D[j] = dim;
            }
        }
        Q.pop();
    }
    calc(G, D, Q2, dim + 1);
}

int main(){
    int n;
    cin >> n;
    vector<vector<int> > G(n + 1, vector<int>(n + 1, 0));
    for (int i = 0; i < n; i++) {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; j++) {
            int v;
            cin >> v;
            G[u][v] = 1;
        }
    }

    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= n; j++) {
            cout << G[i][j] << " ";
        }
        cout << endl;
    }
    cout << endl;

    vector<int> D(n + 1, -1);

    queue<int> Q;
    Q.push(1);
    D[1] = 0;
    calc(G, D, Q, 1);

    for (int i = 1; i <= n; i++) {
        cout << i << " " << D[i] << endl;
    }

    return 0;
}

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

using namespace std;

int n;
int u[102], k[102], t[102][102];
queue<int>Q;
vector<int>V;
int color[102];
int d[102];

void bfs(int s){
  for(int i = 1; i <= n; ++i){
    if(u[i] != s){
      color[u[i]] = 0;
      d[u[i]] = 150;
    }
  }
  d[s] = 0;
  int pi = 0;
  Q.push(s);
  while(!Q.empty()){
    int m = Q.front();
    Q.pop();
    for(int i = 1; i <= k[m]; ++i){
      if(color[t[m][i]] == 0){
        color[t[m][i]] = 2;
        d[t[m][i]] = d[m] + 1;
        pi = t[m][i];
        Q.push(t[m][i]);
      }
    }
    color[m] = 1;
  }
  for(int i = 1; i <= n; ++i){
    if(d[i] == 150){
      cout << i << " " << -1 << endl;
    }else{
      cout << i << " " << d[i] << endl;
    }
  }
  
}

int main(){
  cin >> n;
  for(int i = 1; i <= n; ++i){
    cin >> u[i] >> k[i];
    for(int j = 1; j <= k[i]; ++j){
      cin >> t[i][j];
    }
  }
  bfs(1);
}