Go: package main

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

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)
	nodes := make([]Node, n)

	for i := 0; i < n; i++ {
		nodes[i].list = make([]int, 0)
		nodes[i].d = -1
	}

	for i := 0; i < n; i++ {
		u := getNextInt(scanner)
		k := getNextInt(scanner)
		u--
		for ii := 0; ii < k; ii++ {
			v := getNextInt(scanner)
			v--
			nodes[u].list = append(nodes[u].list, v)
		}
	}

	queue := make([]int, n)
	queue[0] = 0
	nodes[0].d = 0
	d := 0
	i, j := 0, 1
	for i < j {
		d++
		prev := j
		for i < prev {
			for k, l := 0, len(nodes[queue[i]].list); k < l && i < n; k++ {
				if nodes[nodes[queue[i]].list[k]].d != -1 {
					continue
				}
				nodes[nodes[queue[i]].list[k]].d = d
				queue[j] = nodes[queue[i]].list[k]
				j++
			}
			i++
		}
	}

	for i := 0; i < n; i++ {
		fmt.Fprintln(writer, fmt.Sprintf("%d %d", i+1, nodes[i].d))
	}

	writer.Flush()
}

// Node ...
type Node struct {
	list []int
	d    int
}

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[MAX_N];

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

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

  scanf("%d",&n);

  queue = malloc(n * sizeof(int));
  color = malloc(n * sizeof(int));
  dist = 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(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 == n+1){ tail = 0; cout<<'a'<<endl;}
}

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

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

int main(){
    int n;
    cin >> n;
    Graph G(n + 1);
    for (int i = 1; i <= n; i++)
    {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; j++)
        {
            int v; cin >> v;
            G[u].push_back(v);
        }
    }

    vector<int> dist(n + 1, -1);
    queue<int> que;

    dist[1] = 0;
    que.push(1);

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

        for(int nv : G[v]){
            if(dist[nv] != -1) continue;

            dist[nv] = dist[v] + 1;
            que.push(nv);
        }
    }
    
    for (int i = 1; i <= n; i++)
    {
        cout << i << " " << dist[i] << endl;
    }
    
}

C++: #include <iostream>
using namespace std;
int n,g[100][100],f[100],c1[100],c2[100];
void bfs(int now,int far){
  for(int i=0;i<n;i++) if(g[now][i]) f[i]=min(f[i],far+1);
  for(int i=0;i<n;i++) if(g[now][i]&&c1[i]!=1) bfs(i,far+1);
}
int main(){

  int a,b,tmp;
  cin>>n;
  for(int i=0;i<n;i++){
    if(i) f[i]=1000;
    cin>>a>>b;
    for(int j=0;j<b;j++){
      cin>>tmp;
      g[a-1][tmp-1]=1;
    }
  }

  bfs(0,0);

  for(int i=0;i<n;i++) if(f[i]==1000) f[i]=-1;
  for(int i=0;i<n;i++) cout<<i+1<<" "<<f[i]<<endl;

  return 0;

}

C++: #include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); ++i)
using namespace std;
// using ll = long long;
// using P = pair<int, int>;

bool visited[105];
int ans[105];
vector<vector<int> > v(105);

int main() {
    int n;
    cin >> n;
    
    int x, y;
    rep(i, n){
        cin >> x >> y;
        rep(j, y){
            int t;
            cin >> t;
            v[x-1].push_back(t-1);
        }
    }
    
    rep(i, 105){
        visited[i] = false;
        ans[i] = -1;
    }
    
    queue<pair<int, int> > q;
    q.push(make_pair(0, 0));
    visited[0] = true;
    
    while(!q.empty()){
        int node = q.front().first;
        int t_found = q.front().second;
        q.pop();
        rep(i, (int)v[node].size()){
            if(!visited[v[node][i]]){
                q.push(make_pair(v[node][i], t_found+1));
                visited[v[node][i]] = true;
            }
        }
        ans[node] = t_found; 
    }
    
    rep(i, n){
        cout << i+1 << " " << ans[i] << endl;
    }
    
    return 0;
}

C++: #include <iostream>
#include<queue>
using namespace std;
const int MAXn=100;
const int INFTY=1<<21;

int n,M[MAXn][MAXn]={0},d[MAXn];

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

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

C++: #include <iostream>
#include <vector>
#include <list>
#include <cstdlib>

const int MAX_N = 100;

struct Node {
  int v;
  int d;
  bool visited;
};

int main(void) {
  std::cin.tie(0);
  std::ios::sync_with_stdio(false);  

  int n = 0;
  std::cin >> n;

  std::vector<std::vector<int> *> *graph = new std::vector<std::vector<int> *>(n + 1);
  std::vector<struct Node *> *nodes = new std::vector<struct Node *>(n + 1);
  
  for (int i = 1; i <= n; i++) {
    int v = 0;
    std::cin >> v;

    int k = 0;
    std::cin >> k;

    std::vector<int> *neighbors = new std::vector<int>(k);

    for (int i = 0; i < k; i++) {
      int a = 0;
      std::cin >> a;

      neighbors->at(i) = a;
    }

    graph->at(i) = neighbors;

    struct Node *node = (struct Node *) std::malloc(sizeof(struct Node));

    node->v = i;
    node->d = -1;
    node->visited = false;
    
    nodes->at(i) = node;
  }

  int count = 0;
  int start = 1;

  //  nodes->at(start)->d = 1;

  std::list<int> *stack = new std::list<int>();

  stack->push_back(nodes->at(start)->v);

  while (!stack->empty()) {
    std::vector<int> *newNodes = new std::vector<int>();

    while (!stack->empty()) {    
      int v = stack->front();
      stack->pop_front();

      nodes->at(v)->d = count;
      nodes->at(v)->visited = true;
      
      std::vector<int> *neighbors = graph->at(v);

      for (std::vector<int>::iterator iterator = neighbors->begin(); iterator != neighbors->end(); ++iterator) {
	struct Node *node = nodes->at(*iterator);

	if (!node->visited) {
	  newNodes->push_back(node->v);
	}
      }
    }

    for (std::vector<int>::iterator iterator = newNodes->begin(); iterator != newNodes->end(); ++iterator) {
      stack->push_front(*iterator);
    }

    count++;
  }

  for (std::vector<struct Node *>::iterator iterator = nodes->begin() + 1; iterator != nodes->end(); ++iterator) {
    struct Node *node = *iterator;
        
    std::cout << node->v << " " << node->d << std::endl;
  }
  
  return 0;
}