Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

func main() {
	scn := bufio.NewScanner(os.Stdin)
	scn.Split(bufio.ScanWords)
	nextInt := func() int { scn.Scan(); r, _ := strconv.Atoi(scn.Text()); return r }
	w := bufio.NewWriter(os.Stdout)

	n := nextInt()
	vecs := make([][]int, n)
	for i := 0; i < n; i++ {
		u := nextInt()
		k := nextInt()
		for j := 0; j < k; j++ {
			vecs[u-1] = append(vecs[u-1], nextInt()-1)
		}
	}

	ds := make([]int, 0, n)
	for i := 0; i < n; i++ {
		ds = append(ds, -1)
	}

	q := make([]int, 0, n)
	q = append(q, 0)
	ds[0] = 0

	for len(q) > 0 {
		i := pop(&q)
		for _, v := range vecs[i] {
			if ds[v] == -1 {
				ds[v] = ds[i]+1
				q = append(q, v)
			}
		}
	}

	for i, d := range ds {
		fmt.Fprintln(w, i+1, d)
	}

	w.Flush()
}

func pop(q *[]int) int {
	v := (*q)[0]
	*q = (*q)[1:]
	return v
}

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)
{
  queue<int> q;
  q.push(s);
  for(int i=0;i<n;i++) d[i]=infty;
  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]!=infty) continue;
      d[v]=d[u]+1;
      q.push(v);
    }
  }
  for(int i=0;i<n;i++)
  {
    cout<<i+1<<" "<<((d[i]==infty)?(-1):d[i]) <<endl;
  }
}

int main()
{
  //入力
  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);

}

C++: #pragma region kyomukyomupurin

/**
 *    author  : 𝒌𝒚𝒐𝒎𝒖𝒌𝒚𝒐𝒎𝒖𝒑𝒖𝒓𝒊𝒏
 *    created : 2020-06-07 22:12:03
 **/

#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <chrono>
#include <cmath>
#include <complex>
#include <deque>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <utility>
#include <vector>

using namespace std;

using int64 = long long;

template<class T>
inline void eraque(std::vector<T>& vec) {
  vec.erase(std::unique(vec.begin(), vec.end()), vec.end());
  return;
}

template<class T>
inline int lower_position(const std::vector<T>& vec, T value) {
  return static_cast<int>(distance(vec.begin(), std::lower_bound(vec.begin(), vec.end(), value)));
}

template<class T>
inline int upper_position(const std::vector<T>& vec, T value) {
  return static_cast<int>(distance(vec.begin(), std::upper_bound(vec.begin(), vec.end(), value)));
}

template <class T>
using binary_heap = std::priority_queue<T, std::vector<T>, std::greater<T>>;

template <class T, class U>
std::ostream& operator<<(std::ostream& os, const std::pair<T, U>& p) {
  return os << '(' << p.first << ", " << p.second << ')';
}

#if __cplusplus >= 201703L
template <class Ch, class Tr, class Tuple, std::size_t... Is>
void tuple_out(std::basic_ostream<Ch, Tr>& os, const Tuple& tp, std::index_sequence<Is...>) {
  ((os << (Is ? ", " : "(") << std::get<Is>(tp)), ...) << ")";
}

template <class Ch, class Tr, class... Args>
auto& operator<<(std::basic_ostream<Ch, Tr>& os, const std::tuple<Args...>& tp) {
  tuple_out(os, tp, std::index_sequence_for<Args...>{});
  return os;
}
#endif

template <class T>
std::ostream& operator<<(std::ostream& os, const std::vector<T>& vec) {
  int n = 0;
  for (auto e : vec) os << (n++ ? ", " : "{") << e;
  return os << (n ? "}" : "{}");
}

template <class T, class Compare>
std::ostream& operator<<(std::ostream& os, const std::set<T, Compare>& st) {
  int n = 0;
  for (auto e : st) os << (n++ ? ", " : "{") << e;
  return os << (n ? "}" : "{}");
}

template <class T, class U, class Compare>
std::ostream& operator<<(std::ostream& os, const std::map<T, U, Compare>& mp) {
  int n = 0;
  for (auto e : mp) os << (n++ ? ", " : "{") << e;
  return os << (n ? "}" : "{}");
}

template <class T>
std::istream& operator>>(std::istream& is, std::vector<T>& vec) {
  for (T& e : vec) is >> e;
  return is;
}

#define all(_) begin(_), end(_)
#define rall(_) rbegin(_), rend(_)

#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]: ", debug_out(__VA_ARGS__)
#else
#define debug(...)
#endif

void debug_out() { std::cerr << '\n'; }

template <class Head, class... Tail>
void debug_out(Head&& head, Tail&&... tail) {
  std::cerr << head;
  if (sizeof...(Tail) != 0) std::cerr << ", ";
  debug_out(std::forward<Tail>(tail)...);
}

#pragma endregion kyomukyomupurin

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);

  int n; cin >> n;
  vector<vector<int>> g(n);
  for (int i = 0; i < n; ++i) {
    int id, k; cin >> id >> k;
    for (int j = 0; j < k; ++j) {
      int v; cin >> v; --v;
      g[i].emplace_back(v);
    }
  }

  vector<int> dis(n, -1);
  dis[0] = 0;

  queue<int> que;
  que.emplace(0);
  vector<bool> visited(n, false);
  visited[0] = true;

  while (!que.empty()) {
    int cur = que.front(); que.pop();
    for (int nxt : g[cur]) {
      if (visited[nxt]) continue;
      dis[nxt] = dis[cur] + 1;
      visited[nxt] = true;
      que.emplace(nxt);
    }
  }

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

  return 0;
}

C++: #include<cstdio>
#include<algorithm>
#include<queue>
#include<vector>
#include<map>
using namespace std;
typedef pair< int, int > Pi;
const int INF = 1 << 30;
struct edge: vector< Pi > {
  void add_edge(int to, int cost){
    push_back(Pi(to,cost));
  }
} info[100000];
int hoge[100000];
 
void bfs(const int& st, const int& V){
  fill_n( hoge, V, INF);
  queue< int > que;
  que.push(st);
  hoge[st] = 0;
  while(!que.empty()){
    int p = que.front();
    que.pop();
    for(int i = 0 ; i < info[p].size() ; i++){
      int cost = info[p][i].second;
      int to = info[p][i].first;
      if( cost + hoge[p] < hoge[to]){
        que.push(to);
        hoge[to] = cost + hoge[p];
      }
    }
  }
}
 
int main(){
  int N;
  scanf("%d", &N);
  for(int i = 0; i < N; i++){
    int u, k;
    scanf("%d %d", &u, &k);
    u--;
    while(k--){
      int v;
      scanf("%d", &v);
      info[u].add_edge( v - 1, 1);
    }
  }
  bfs(0, N);
  for(int i = 0 ; i < N ; i++ ){
    printf("%d %d\n", i + 1, hoge[i]);
  }
}