Go: package main

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

var distance []int

type queue struct {
	q    []int
	head int
	tail int
}

func (q *queue) push(n int) {
	q.q[q.tail] = n
	q.tail++
}

func (q *queue) pop() int {
	q.head++
	return q.q[q.head-1]
}

func (q *queue) isEmpty() bool {
	return q.head == q.tail
}

func makeAdjList() [][]int {
	var n int
	fmt.Scanf("%d", &n)

	adj := make([][]int, n)
	for i := 0; i < n; i++ {
		adj[i] = make([]int, n)
	}

	sc := bufio.NewScanner(os.Stdin)
	for i := 0; i < n; i++ {
		sc.Scan()
		nodeInfo := strings.Split(sc.Text(), " ")
		outDegree, _ := strconv.Atoi(nodeInfo[1])

		if outDegree > 0 {
			for k := 0; k < outDegree; k++ {
				j, _ := strconv.Atoi(nodeInfo[k+2])
				j-- // convert 1 based to 0 based
				adj[i][j] = 1
			}
		}
	}

	return adj
}

func bfs(graph [][]int, s int) {
	distance = make([]int, len(graph))

	infty := -1
	for i := 0; i < len(distance); i++ {
		distance[i] = infty
	}
	distance[s] = 0

	q := &queue{make([]int, 1000), 0, 0}
	q.push(s)

	for !q.isEmpty() {
		u := q.pop()
		for i := 0; i < len(graph); i++ {
			if graph[u][i] == 0 {
				continue // u, i間に辺がない場合
			}
			if distance[i] != infty {
				continue // 訪問済みの場合
			}
			// 訪問するnodeの始点からの距離を設定し、訪問キューに入れる
			distance[i] = distance[u] + 1
			q.push(i)
		}
	}

	// print distance
	for i, d := range distance {
		fmt.Printf("%d %d\n", i+1, d)
	}
}

func main() {
	adj := makeAdjList()
	bfs(adj, 0)
}

C++: // includes
#include <bits/stdc++.h>
using namespace std;

// macros
#define pb emplace_back
#define mk make_pair
#define FOR(i, a, b) for(int i=(a);i<(b);++i)
#define rep(i, n) FOR(i, 0, n)
#define rrep(i, n) for(int i=((int)(n)-1);i>=0;i--)
#define irep(itr, st) for(auto itr = (st).begin(); itr != (st).end(); ++itr)
#define irrep(itr, st) for(auto itr = (st).rbegin(); itr != (st).rend(); ++itr)
#define whole(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
#define bit(n) (1LL<<(n))
// functions
template <typename T> void unique(T& c){c.erase(std::unique(c.begin(), c.end()), c.end());}
template <class T>bool chmax(T &a, const T &b){if(a < b){a = b; return 1;} return 0;}
template <class T>bool chmin(T &a, const T &b){if(a > b){a = b; return 1;} return 0;}
template <typename T> istream &operator>>(istream &is, vector<T> &vec){for(auto &v: vec)is >> v; return is;}
template <typename T> ostream &operator<<(ostream &os, const vector<T>& vec){for(int i = 0; i < vec.size(); i++){ os << vec[i]; if(i + 1 != vec.size())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const set<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const unordered_set<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const multiset<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const unordered_multiset<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &p){os << "(" << p.first << ", " << p.second << ")"; return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const map<T1, T2> &mp){for(auto itr = mp.begin(); itr != mp.end(); ++itr){ os << "(" << itr->first << ", " << itr->second << ")"; auto titr = itr; if(++titr != mp.end())os << " "; } return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const unordered_map<T1, T2> &mp){for(auto itr = mp.begin(); itr != mp.end(); ++itr){ os << "(" << itr->first << ", " << itr->second << ")"; auto titr = itr; if(++titr != mp.end())os << " "; } return os;}
//  types
using ll = long long int;
using P = pair<int, int>;
// constants
const int inf = 1e9;
const ll linf = 1LL << 50;
const double EPS = 1e-10;
const int mod = 1000000007;
const int dx[4] = {-1, 0, 1, 0};
const int dy[4] = {0, -1, 0, 1};
// io
struct fast_io{
  fast_io(){ios_base::sync_with_stdio(false); cin.tie(nullptr); cout << fixed << setprecision(20);}
} fast_io_;

template <typename T>
struct Graph {
  int n;
  vector<vector<pair<int, T> > > edge;
  vector<T> dis;
  Graph(int n): n(n) {
    edge.resize(n);
    dis.resize(n);
  }
  void dijkstra(int s){
    dijkstra(s, 0);
  }
  T dijkstra(int s, int t){
    // initialize
    fill(dis.begin(), dis.end(), -1);
    vector<bool> used(n, false);
    dis[s] = 0;
    // dijkstra
    priority_queue<pair<T, int>, vector<pair<T, int> >, greater<pair<T, int> > > q;
    q.push(make_pair(0, s));
    while(!q.empty()){
      pair<T, int> p = q.top(); q.pop();
      int at = p.second;
      T distance = p.first;
      if(used[at])continue;
      used[at] = true;
      for(auto itr = edge[at].begin(); itr != edge[at].end(); ++itr){
        int to = (*itr).first;
        T cost = (*itr).second;
        if(used[to])continue;
        if(dis[to] == -1 || dis[to] > distance + cost){
          q.push(make_pair(distance + cost, to));
          dis[to] = distance + cost;
        }
      }
    }
    return dis[t];
  }
  void adde(int at, int to, T cost){
    edge[at].push_back(make_pair(to, cost));
  }
  [[deprecated("This function takes O(|edge[at]|).")]]
  void remove(int at, int to){
    int index = -1;
    for(int i = 0; i < edge[at].size(); i++){
      if(edge[at][i].first == to){
        index = i;
        break;
      }
    }
    edge[at].erase(edge[at].begin() + index);
  }
};

using GraphI = Graph<int>;
using GraphL = Graph<ll>;
using GraphD = Graph<double>;


int main(int argc, char const* argv[])
{
  int n; cin >> n;
  GraphI g(n);
  rep(i, n){
    int x; cin >> x; x--;
    int k; cin >> k;
    rep(j, k){
      int c; cin >> c; c--;
      g.adde(x, c, 1);
    }
  }
  g.dijkstra(0);
  rep(i, n){
    cout << i + 1 << " " << g.dis[i] << endl;
  }
  return 0;
}

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

static const int INFTY = 1<<21;

/*
enum Color{
    WHITE,
    GRAY,
    BLACK
};
*/

int n;
deque<int> Q;
int d[100]; //距離で色も表せる
bool M[100][100];
//Color color[100];


void dfs(int i){
    for(int j=0; j<n; j++){
        //color[i] = WHITE;
        d[j] = INFTY;   //色の要素も兼ねている
    }

    //color[i] = GRAY;
    d[i] = 0;
    Q.push_back(i);

    while(!Q.empty()){
        int u = Q.front();
        Q.pop_front();
        for(int v=0; v<n; v++){
            if((M[u][v]==true)&&(d[v]==INFTY)){
                //color[u] = GRAY;
                d[v] = d[u] + 1;
                Q.push_back(v);
            }
        }
        //color[u] = BLACK;
    }

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

int main(){

    cin >> n; 

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

    dfs(0);

    return 0;
}