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;

int n, M[100][100], d[100];

void bfs (int s) {

    int i, u, v;

    queue<int> Q;
    Q.push(s);
    for (i = 0; i < n; i++) {
        d[i] = (1 << 21);
    }
    d[s] = 0;
    while (!Q.empty()) {
        u = Q.front();
        Q.pop();
        for (v = 0; v < n; v++) {
            if (M[u][v] == 0) {
                continue;
            }
            if (d[v] != (1 << 21)) {
                continue;
            }
            d[v] = d[u] + 1;
            Q.push(v);
        }
    }
    for (i = 0; i < n; i++) {
        cout << i + 1 << " " << ((d[i] == (1 << 21)) ? (-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;

}

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

const int MAXINT = std::numeric_limits<int>::max();

void bfs(std::vector<std::vector<int> >& adj_list, std::vector<int>& d, int root = 0 ){
  std::queue<int> target_q;
  // std::queue<int> dist_q;
  target_q.push(root);
  d[root] = 0;
  // dist_q.push(0;)
  while(!target_q.empty()){
    int vtx = target_q.front(); target_q.pop();
    for(int const&  u : adj_list[vtx]){
      target_q.push(u);
      if(d[vtx] + 1 < d[u]){
        // std::cout<< "/* message */" << std::endl;
        d[u] = d[vtx] + 1;
      }
    }
  }
}


int main(int argc, char const *argv[]) {
  int n; // .. 100
  std::cin >> n;
  std::vector<std::vector<int> > adj_list(n);
  std::vector<int> d(n, MAXINT);

  for(int q=0; q<n; ++q){
    int i_plus_1, k;
    std::cin >> i_plus_1;
    std::cin >> k;
    for(int p=0; p<k; ++p){
      int j_plus_1;
      std::cin >> j_plus_1;
      // adj[i_plus_1-1][j_plus_1-1] = true;
      adj_list[i_plus_1 - 1].push_back(j_plus_1-1);
    }
  }
  bfs(adj_list, d, 0);

  for(int i=0; i<n; ++i){

    // if(d[i] < MAXINT){
      std::cout << (i+1)
        << " " << d[i]
        << std::endl;
  }


  // for(auto it = adj_list.begin(); it != adj_list.end(); ++it){
  //   std::cout << ": ";
  //   for(auto jt = (*it).begin(); jt != (*it).end(); ++jt){
  //     std::cout << (*jt) << ' ';
  //   }
  //   std::cout << std::endl;
  // }

  return 0;
}

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

#define MAX_NODE 100
#define INF 1000000000

using namespace std;

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

void bfs(int n, int start) {
	queue<int> que;

	for (int i = 0; i < n; i++)
		d[i] = (i == start ? 0 : INF);

	que.push(start);
	while(!que.empty()) {
		int from = que.front();
		que.pop();

		for (int i = 0; i < adj[from].size(); i++) {
			int to = adj[from][i];
			if (d[to] == INF) {
				d[to] = d[from] + 1;
				que.push(to);
			}
		}
	}
}

int main() {
	int n;

	cin >> n;

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

	bfs(n, 0);

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

	return 0;
}

C++: #include <stdio.h>
#include <vector>
#include <queue>
using namespace std;

vector<int> G[101];
bool visit[101];
int n, u, k, m;
int dist[101];

void bfs()
{
	int root = 1;
	queue<int> que;
	que.push(root);
	dist[root] = 0;
 visit[root] = true;
	while (!que.empty())
	{
		int node = que.front();
		que.pop();
		for (int i = 0; i < G[node].size(); i++)
		{
			int next = G[node][i];
			if (!visit[next])
			{
				visit[next] = true;
				que.push(next);
				dist[next] = dist[node] + 1;
			}
		}
	}
}

int main()
{
	for (int i = 0; i < sizeof(dist) / sizeof(dist[0]); i++)
		dist[i] = -1;
	scanf("%d", &n);
	for (int i = 0; i < n; i++)
	{
		scanf("%d%d", &u, &k);
		for (int j = 0; j < k; j++)
		{
			scanf("%d", &m);
			G[u].push_back(m);
		}
	}
	bfs();
	for (int i = 1; i <= n; i++)
		printf("%d %d\n", i, dist[i]);

	return 0;
}

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

using namespace std;

void bfs(int src, int n, vector<vector<int> > G);

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

void bfs(int src, int n, vector<vector<int> > G) {
	vector<int> D(n, -1);
	D[src] = 0;
	queue<int> Q;
	Q.push(src);
	while (!Q.empty()) {
		int cur = Q.front();
		Q.pop();
		for (int dst = 0; dst < n; dst++)
			if (G[cur][dst] == 1 && D[dst] == -1){
				D[dst] = D[cur] + 1;
				Q.push(dst);
			}
	}
	for (int i = 0; i < n; i++)
		cout << i + 1 << " " << D[i] << endl;
}

C++: #include <stdio.h>
#include <stdlib.h>

#define WHITE 0
#define GRAY 1
#define BLACK 2
#define MAX_N 100

int n,time,head,tail;
int *queue;
int *dist;
int *color;
int **matrix;

void enqueue(int);
int dequeue(void);
void bfs(void);

int main(){
  int i,j,u,k,v;

  scanf("%d",&n);

  queue = malloc(MAX_N * sizeof(int));
  color = malloc(n * sizeof(int));
  dist = malloc(n * sizeof(int));

  matrix = malloc(n * sizeof(int *));
  for(i = 0 ; i < n ; i++){
    matrix[i] = malloc(n * sizeof(int));
 }
 for(i = 0 ; i < n ; i++){
   dist[i] = -1;
 }
 for(i = 0 ; i < n ; i++){
   for(j = 0 ; j < n ; j++){
     matrix[i][j] = 0;
   }
 }

 for(i = 0 ; i < n ; i++){
    scanf("%d",&u); u--;
    scanf("%d",&k);
    for(j = 0 ; j < k ; j++){
      scanf("%d",&v); v--;
      matrix[u][v] = 1;
    }
  }

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

  for(i = 0 ; i < n ; i++){
    free(matrix[i]);
  }
  free(matrix);
  free(queue);
  free(dist);
  free(color);
  return 0;
}

void bfs(){
  int u,i;

  head = tail = 0;
  color[0] = GRAY;
  dist[0] = 0;
  enqueue(0);

  while(head != tail){
    u = dequeue();
    for(i = 0 ; i < n ; i++){
      if(matrix[u][i] == 1 && color[i] == WHITE){
        color[i] = GRAY;
        dist[i] = dist[u] + 1;
        enqueue(i);
      }
    }
    color[u] = BLACK;
  }
}

void enqueue(int q){
  queue[tail] = q;
  if(++tail == MAX_N+1) tail = 0;
}

int dequeue(){
  int v = queue[head];
  if(++head == MAX_N+1) head = 0;
  return v;
}