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], 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() {
	int v, k ,u;
	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;
		for(int j = 0; j < k; j++) {
			cin >> v;
			M[u-1][v-1] = 1;
		}
	}
	
	bfs(0);
	
	return 0;
	
}

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

using namespace std;

#define MAX 100

#define WHITE 0
#define GRAY 1
#define BLACK 2

int T;
int N;

int M[MAX][MAX];
int C[MAX],D[MAX];

void bfs(int s)
{
    queue<int> *q = new queue<int>;

    q->push(s);
    D[s] = 0;
    C[s] = GRAY;

    while(q->size() > 0)
    {
        int u = q->front();
        q->pop();

        for (int i = 0; i < N; i++)
        {
            if (M[u][i] && C[i] == WHITE)
            {
                C[u] = GRAY;
                D[i] = D[u] + 1;
                q->push(i);
            }
        }

        C[u] = BLACK;
    }
}

int main ()
{
    cin >> N;

    for (int i = 0; i < N; i++)
    {
        C[i] = WHITE;
        D[i] = -1;

        for (int j = 0; j < N; j++)
        {
            M[i][j] = 0;
        }
    }

    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] = 1;
        }
    }

    for (int i = 0; i < N; i++)
    {
        for (int j = 0; j < N; j++)
        {
            if (j > 0)
                cout << " ";
            cout << M[i][j];
        }
        cout << endl;
    }

    bfs(0);

    for (int i = 0; i < N; i++)
    {
        cout << D[i] << endl;
    }

    return 0;
}

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

typedef vector<int> Adj_list;
typedef vector<Adj_list> Adj_lists;

void bfs(const int& i, const Adj_lists& adj_lists, vector<int>& distances){

  distances.at(i-1) = 0;

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

  while(!q.empty()){
    // visit top of queue
    const int& visit = q.front();
    const Adj_list& adj_list = adj_lists.at(visit-1);

    // push adjecent node which is not visited yet
    for(const int& adj : adj_list){
      if(distances.at(adj-1) == -1){
        distances.at(adj-1) = distances.at(visit-1) + 1;
        q.push(adj);
      }
    }

    q.pop();
  }
}

int main(){

  int n;
  scanf("%d", &n);

  Adj_lists adj_lists(n);
  for(int i=0; i<n; i++){
    int u, k;
    scanf("%d %d", &u, &k);
    Adj_list adj_list(k);
    for(int j=0; j<k; j++){
      int v;
      scanf("%d", &v);
      adj_list[j] = v;
    }
    sort(adj_list.begin(), adj_list.end());
    adj_lists[u-1] = adj_list;
  }

  vector<int> distances(n);
  for(int& distance : distances) distance = -1;

  bfs(1, adj_lists, distances);

  for(int i = 0; i < distances.size(); i++){
    printf("%d %d\n", i+1, distances.at(i));
  }

  return 0;
}

C++: #include <cstdint>
#include <queue>
#include <vector>

using namespace std;

#define GRAPH_SIZE 101
#define START_INDEX 1

enum color_t {
  WHITE,
  GRAY,
  BLACK,
};

struct data_t {
  uint32_t index;
  vector<uint32_t> connection;
  uint32_t distance;
};

static vector<uint32_t> graph[GRAPH_SIZE];
static color_t state[GRAPH_SIZE];

void breadth_first_search(void (*callback)(uint32_t, uint32_t))
{
  for (uint32_t i = START_INDEX; i < GRAPH_SIZE; i++) {
    state[i] = WHITE;
  }

  queue<data_t> queue;

  data_t data;
  data.index = START_INDEX;
  data.connection = graph[START_INDEX];
  data.distance = 0;

  queue.push(data);
  state[START_INDEX] = GRAY;

  while (!queue.empty()) {
    data_t top = queue.front();
    queue.pop();

    state[top.index] = BLACK;
    callback(top.index, top.distance);

    for (uint32_t i = 0; i < top.connection.size(); i++) {
      if (state[top.connection[i]] == WHITE) {
        data_t data;
        data.index = top.connection[i];
        data.connection = graph[top.connection[i]];
        data.distance = top.distance + 1;
        queue.push(data);
        state[data.index] = GRAY;
      }
    }
  }
}

#include <iostream>

int32_t distances[GRAPH_SIZE];

static void callback(uint32_t index, uint32_t distance)
{
  distances[index] = distance;
}

int32_t main()
{
  uint32_t num;
  cin >> num;

  for (uint32_t i = START_INDEX; i < START_INDEX + num; i++) {
    distances[i] = -1;
  }

  for (uint32_t i = 0; i < num; i++) {
    uint32_t index, len;
    cin >> index >> len;
    for (uint32_t j = 0; j < len; j++) {
      uint32_t val;
      cin >> val;
      graph[index].push_back(val);
    }
  }

  breadth_first_search(callback);

  for (uint32_t i = START_INDEX; i < START_INDEX + num; i++) {
    cout << i << " " << distances[i] << endl;
  }

  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> P;
constexpr int di[] = {0, 1, 0, -1}, dj[] = {1, 0, -1, 0};
#define rep(i, n) for (int i = 0; i < n; i++)
#define repr(i, n) for (int i = n; i >= 0; i--)
#define sort(v) sort((v).begin(), (v).end())
#define sortr(v) sort((v).rbegin(), (v).rend())
#define all(v) (v).begin(), (v).end()
#define max 100005
#define nil -1

constexpr int inf = 1000000;
vector<vector<int>> g;
vector<int> d;

void bfs(int s){
    d.resize(max);
   fill(d.begin(),d.end(),inf);
   d[s]=0;
   queue<int> q;
   q.push(s);
   while(!q.empty()){
       int now=q.front();
       q.pop();
       for(auto &e:g[now]){
           if(d[e]==inf){
               d[e]=d[now]+1;
               q.push(e);
           }
       }
   }
}

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

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

using namespace std;
using Graph = vector<vector<int>>;

int main() {
	int n;
	cin >> n;

	Graph G(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--;
			G[u].push_back(v);
		}
	}

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

	while (!q.empty()) {
		int v = q.front();
		q.pop();

		for (int nv : G[v]) {
			if (dist[nv] != -1) continue;
			dist[nv] = dist[v] + 1;
			q.push(nv);
		}
	}

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

	return 0;
}