Go: package main

import (
	"container/list"
	"fmt"
	"bufio"
	"os"
	"strconv"
)

const (
	N   = 100
	INF = 1 << 21
)

var (
	n        int
	adj      [N][N]int
	distance [N]int
)

func BFS(start int) {
	q := list.New()
	q.PushBack(start)
	for i := 0; i < n; i++ {
		distance[i] = INF
	}
	distance[start] = 0
	u := 0
	for q.Len() != 0 {
		u = q.Remove(q.Front()).(int)
		for v := 0; v < n; v++ {
			if adj[u][v] == 0 {
				continue
			}
			if distance[v] != INF {
				continue
			}
			distance[v] = distance[u] + 1
			q.PushBack(v)
		}
	}
	for i := 0; i < n; i++ {
		var d int
		if distance[i] == INF {
			d = -1
		} else {
			d = distance[i]
		}
		fmt.Printf("%d %d\n", i+1, d)
	}
}

func main() {
	var u, k, v int
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	scanner.Scan()
	n, _ = strconv.Atoi(scanner.Text())
	for i := 0; i < n; i++ {
		for j := 0; j < n; j++ {
			adj[i][j] = 0
		}
	}
	for i := 0; i < n; i++ {
		scanner.Scan()
		u, _ = strconv.Atoi(scanner.Text())
		u -= 1
		scanner.Scan()
		k, _ = strconv.Atoi(scanner.Text())
		for j := 0; j < k; j++ {
			scanner.Scan()
			v, _ = strconv.Atoi(scanner.Text())
			v -= 1
			adj[u][v] = 1
		}
	}
	BFS(0)
}

C++: #include <iostream>
#include <vector>
#include <cmath>
#include <algorithm>
#include <numeric>
#include <stack>
#include <queue>
#include <deque>
#include <iomanip>
#include <string>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <tuple>
#include <bitset>

/*----------------------------------------------------------------*/

using ld = long double;
using vld = std::vector<ld>;
using ll = long long;
using vll = std::vector<ll>;
using vvll = std::vector<vll>;
using str = std::string;
using vstr = std::vector<str>;
using vb = std::vector<bool>;
using vvb = std::vector<vb>;

/*----------------------------------------------------------------*/

template<typename T> bool chmin(T a, T &b) { return a < b ? b = a, true : false; }
template<typename T> bool chmax(T a, T &b) { return a > b ? b = a, true : false; }
template<typename T> T sqr(T a) { return a * a; }

/*----------------------------------------------------------------*/

constexpr ld PI = 3.141592653589793L;
constexpr ld EPS = std::numeric_limits<ld>::epsilon();

/*----------------------------------------------------------------*/

ll gcd(ll n, ll m) { return m ? gcd(m, n % m) : n; }
ll lcm(ll n, ll m) { return n / gcd(n, m) * m; }
bool is_prime(ll n) {
    if (n == 1) return false;
    for (ll i = 2; sqr(i) <= n; i++)
        if (n % i == 0) return false;
    return true;
}
ll popcnt(ll n) {
    n = ((n & 0xaaaaaaaaaaaaaaaa) >> 1) + (n & 0x5555555555555555);
    n = ((n & 0xcccccccccccccccc) >> 2) + (n & 0x3333333333333333);
    n = ((n & 0xf0f0f0f0f0f0f0f0) >> 4) + (n & 0x0f0f0f0f0f0f0f0f);
    n = ((n & 0xff00ff00ff00ff00) >> 8) + (n & 0x00ff00ff00ff00ff);
    n = ((n & 0xffff0000ffff0000) >> 16) + (n & 0x0000ffff0000ffff);
    n = ((n & 0xffffffff00000000) >> 32) + (n & 0x00000000ffffffff);
    return n;
}

/*----------------------------------------------------------------*/

void solve();

/*----------------------------------------------------------------*/

int main() {
    std::cin.tie(0);
    std::ios::sync_with_stdio(false);
    std::cout << std::setprecision(15);

    solve();
}

void solve() {
    ll n; std::cin >> n;

    vvll g(n);
    for (ll i = 0; i < n; i++) {
        ll u, k; std::cin >> u >> k;
        u--;
        for (ll j = 0; j < k; j++) {
            ll v; std::cin >> v; v--;
            g[u].push_back(v);
        }
    }

    vll dist(n, -1); dist[0] = 0;

    auto bfs = [&](ll x) {
        std::deque<ll> next;
        next.push_back(x);
        while (!next.empty()) {
            ll cur = next.front();
            next.pop_front();
            for (ll i : g[cur])
                if (dist[i] == -1) {
                    dist[i] = dist[cur] + 1;
                    next.push_back(i);
                }
        }
    };

    bfs(0);

    for (ll i = 0; i < n; i++)
        std::cout << i + 1 << ' ' << dist[i] << '\n';
}

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

#define MAX_NODE 10000
#define INF 1000000000

using namespace std;

int d[MAX_NODE];
vector<int> adj[MAX_NODE];

int bfs(int n, int start){
	queue<int> que;
	for(int i=0;i<n;i++){
		d[i]=(i==start)?0:-1;
	}
	que.push(start);
	while(que.empty()==0){
		int from=que.front();
		que.pop();
		for(int i=0;i<adj[from].size();i++){
			int to=adj[from][i];
			if(d[to]==-1){
				d[to]=d[from]+1;
				que.push(to);
			}
		}
	}
}	

int main(){
	int n,u,k,v;
	cin>>n;
	for(int i=0;i<n;i++){
		cin>>u>>k;
		for(int j=0;j<k;j++){
			cin>>v;
			v--;
			adj[u-1].push_back(v);
		}
	}
	cout<<adj[0].size()<<endl;
	bfs(n,0);
	for(int i=0;i<n;i++){
		cout<<i+1<<" "<<d[i]<<endl;
	}
	return 0;
}

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

using namespace std;
static const int N=100;
static const int INFTY =(1<<21);

int n,M[N][N];
int d[N];

void bfs(int s){
  int i,v;
  queue<int> q;
  q.push(s);
  for(i=0;i<n;i++) d[i]=INFTY;
  d[s]=0;
  int u;

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

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

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

  bfs(0);
  
  return 0;
}