Go: package main

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

const MAX = 1000
const NIL = -1

type Node struct {
	id    int
	depth int
}

type Queue struct {
	head      int
	tail      int
	container [MAX]Node
}

func (q *Queue) inQueue(x Node) {
	q.container[q.tail] = x
	q.tail = (q.tail + 1) % MAX
}

func (q *Queue) deQueue() Node {
	x := q.container[q.head]
	q.head = (q.head + 1) % MAX
	return x
}

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

var sc = bufio.NewScanner(os.Stdin)

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

func main() {
	n := scanInt()
	route := make([][]int, n)
	for i := range route {
		u, k := scanInt(), scanInt()
		u--
		route[u] = make([]int, k)
		for j := range route[u] {
			num := scanInt()
			num--
			route[i][j] = num
		}
	}

	d := make([]int, n)
	for i := range d {
		d[i] = NIL
	}

	start := Node{0, 0}
	que := Queue{}
	que.inQueue(start)
	for !que.isEmpty() {
		node := que.deQueue()
		if d[node.id] != NIL {
			continue
		}
		d[node.id] = node.depth

		for _, nextId := range route[node.id] {
			next := Node{id: nextId, depth: node.depth + 1}
			que.inQueue(next)
		}
	}

	for i, depth := range d {
		fmt.Println(i+1, depth)
	}
}

C++: #include<iostream>
#include<cstdio>
#define INF 1<<30
#define MAX 100000
using namespace std;
class Queue{
private:
  int inf[MAX];
  int head,tail;
 
public:
 
  Queue(){
    syokika();
  }
 
  void syokika(){
    head = 0;
    tail = 0;
  }
 
  void push(int x){
    inf[tail]=x;
    if(MAX == tail+1)tail = 0;
    else tail++;
  }
 
  void pop(){
    if(MAX == head+1)head=0;
    else head++;
  }
 
  int front(){
    return inf[head];
  }
 
  bool empty(){
    if(tail - head == 0)return true;
    else return false;
  }
 
  int size(){
    return tail - head;
  }
 
};

int imap[200][200];
int k[200] = {0}; 
int ans[200] = {0};
bool used[200] ={false};

 



int main(){
  int n,u[1000];
  cin >> n;
  for(int i=0;i<200;i++)for(int j=0;j<200;j++)imap[j][i] = INF;  
  for(int i=0;i<n;i++){
    cin >> u[i];
    cin >> k[u[i]];
    for(int j=0;j<k[u[i]];j++){
      cin >> imap[u[i]][j];
    }
  }
  /*
  for(int i=0;i<n;i++){
    for(int j=0;j<k[i]){


    }
    cout << endl;
  }
*/
  Queue que = Queue();

  que.push(u[0]);

  while(!que.empty()){
    int p = que.front(); que.pop();
    for(int i=0;i<k[p];i++){
      if(!used[imap[p][i]]){
	que.push(imap[p][i]);
	used[imap[p][i]] = true;
	ans[imap[p][i]] = ans[p] + 1;
      }
    }
  }


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


  return 0;
}

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(){
    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);
return 0;
}

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

int main()
{
 int i;
}

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(){
  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);

  return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <string>
#include <stack>
#include <cstdlib>
#include <queue>
#include <vector>
#include <set>

using namespace std;
int n,m,l,p;
int a[100][100];
int D[100];
void bfs( int src) {
	queue<int> Q;
	Q.push(src);
	D[src]=0;
	while( ! Q.empty() ) {
		int cur = Q.front();
		Q.pop();
		for(int dst = 0; dst < n; dst++ ) {
			if( D[dst] < 1 && a[cur][dst] == 1 ) {
				D[dst] = D[cur] + 1;
				Q.push(dst);
			}
		}
	}
	for (int i = 0; i < n;i++) {
	cerr << i+1 <<  " " << D[i] <<  endl;
	}
}

int main() {
	cin >> n;
	for ( int i = 0;i < n;i++) {
		D[i] = -1;
		for(int j= 0; j < n;j++) {
			a[i][j] = 0;
		}
	}
	for (int i = 0;i < n; i++){
		cin >> m;
		cin >> l;
		for(int j = 0; j < l;j++) {
			cin >> p;
			a[m-1][p-1] = 1;
		}
	}
	bfs(0);
}

C++: #include <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define rep(i,n)   FOR(i,0,n)
#define pb emplace_back
typedef long long ll;
typedef pair<int,int> pint;

vector<int> g[101];
bool used[101];
int ans[101];
void bfs(int sr){
    queue<pint> q;q.push({sr,0});
    used[sr]=true;
    while(!q.empty()){
        pint pi=q.front();q.pop();
        ans[pi.first]=pi.second;
        rep(i,g[pi.first].size()){
            int nx=g[pi.first][i];
            if(!used[nx]){
                used[nx]=true;
                q.push({nx,pi.second+1});
            }
        }
    }
}
int main(){
    int n,u,k,v;
    cin>>n;
    rep(i,n){
        cin>>u>>k;
        --u;
        rep(j,k){
            cin>>v;
            --v;
            g[u].pb(v);
        }
    }
    memset(ans,-1,sizeof(ans));
    bfs(0);
    rep(i,n) cout<<i+1<<" "<<ans[i]<<endl;
    return 0;
}

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;
}