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<algorithm>
#include<iostream>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<vector>
#include<queue>
#include<stack>
#include<cmath>
#include<list>
#include<map>
#include<set>
using namespace std;

typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef stack<int> SI;
typedef queue<int> QI;
typedef pair<int,int> PII;
typedef long long LL;

#define d(x)  cout<<#x<<" = "<<(x)<<endl;
#define c cout<<"#"<<endl;
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define REACH(i,c) for(typeof((c).rbegin()) i=(c).rbegin(); i!=(c).rend(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c,n) sort(c,c+n)
#define VSORT(c) sort((c).begin(),(c).end())
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define DFOR(i,b,a) for(int i=(b)-1;i>=(a);--i)
#define DREP(i,n) DFOR(i,n,0)
#define INF 2000000000

const double EPS = 1e-10;
const double PI  = acos(-1.0);
////////////////////////////////////////////////
int n,a[101][101],d[101],p[101];
QI q;
int main()
{
	cin>>n;
	FOR(i,1,n+1)
	{
		int k,m;cin>>k>>m;
		a[k][0]=m;
		FOR(j,1,m+1)
		{	
			int x;cin>>x;
			a[k][j]=x;
		}
	}
	REP(i,101)p[i]=1;
	for(q.push(1);SZ(q)!=0;)
	{
		int u=q.front();
		q.pop();
		for(;p[u]<=a[u][0];)
		{
			int v=a[u][p[u]];p[u]++;
			if(v!=1&&d[v]==0)
			{
				d[v]=d[u]+1;
				q.push(v);
			}
		}
	}
	FOR(i,1,n+1)
	{
		cout<<i<<" "<<d[i]<<endl;
	}
	return 0;
}

C++: #include <queue>
#include <map>
#include <cstdio>

using namespace std;

int main(){
	int t=0,T,i,j,k;
	map<int,vector<int> >a;
	for(scanf("%d",&T); t<T; t++)for(scanf("%d%d",&i,&k); k--; a[i].push_back(j))scanf("%d",&j);
	map<int,int>m;
	queue<int>q;
	for(q.push(1),m[1]=1;!q.empty();){
		k = q.front();
		q.pop();
		for (i = 0; i < a[k].size(); i++){
		    if(!m[a[k][i]])m[a[k][i]]=m[k]+1,q.push(a[k][i]);
		}
	}
	for(i=1;i<=T;i++){
	    printf("%d %d\n",i,m[i]-1);
	}
}

C++: #include<iostream>
#include<queue>
using namespace std;
int map[101][101];
int all = 0;
int search_2[101];
int n;
void bfs(int k, int m) {
	search_2[k] = m;
	queue<int>q;
	for (int i = 2; i <= n; i++) {
		if (map[k][i] && (search_2[i] == 0 || search_2[i] > m + 1)) {
			q.push(i);
		}
	}
	while (!q.empty())
	{
		bfs(q.front(), m + 1);
		q.pop();
	}
}
int main(void) {
	cin >> n;
	for (int i = 0; i < n; i++) {
		int a;
		cin >> a;
		int m;
		cin >> m;
		for (int j = 0; j < m; j++) {
			int b;
			cin >> b;
			map[a][b] = 1;
		}
	}
	bfs(1, 0);
	cout << 1 << " " << 0 << endl;
	for (int i = 2; i <= n; i++) {
		cout << i << " ";
		if (search_2[i] == 0) cout << -1 << endl;
		else cout << search_2[i] << endl;
	}
}

C++: ///
// File:  alds1_11_c.cpp
// Author: ymiyamoto
//
// Created on Wed Oct 18 00:49:05 2017
//

#include <cstdint>
#include <iostream>
#include <queue>
#include <vector>

using namespace std;
static uint32_t graph[100][100];
static vector<int32_t> d(100, -1);
static queue<uint32_t> q;

static void bfs(uint32_t n)
{
  q.push(0);
  d[0] = 0;

  while (!q.empty()) {
    uint32_t index = q.front();
    q.pop();

    for (uint32_t i = 0; i < n; i++) {
      if (d[i] == -1 && graph[index][i] == 1) {
        q.push(i);
        d[i] = d[index] + 1;
      }
    }
  }
}

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

  for (uint32_t i = 0; i < n; i++) {
    uint32_t id, k;
    cin >> id >> k;
    for (uint32_t j = 0; j < k; j++) {
      uint32_t val;
      cin >> val;
      graph[id - 1][val - 1] = 1;
    }
  }

  bfs(n);

  for (uint32_t i = 0; i < n; i++) {
    if (i != 0) cout << " ";
    cout << d[i];
  }
  cout << endl;

  return 0;
}

C++: #include<iostream>
#include<cstdio>
#define N 101
using namespace std;

typedef struct{
  int q[10000];
  int head;
  int tail;
}Queue;

//queue
Queue que;
int g[N][N]; 
int n;
int d[N];
bool us[N];
void Enque(int data){
  que.q[que.tail]=data;
  que.tail++;
}

int Deque(void){
  int data;
  data=que.q[que.head];
  que.head++;
  return data;
}

bool isEmpty(){
  if(que.tail-que.head==0)return true;
  else return false;
}

//bfs
void bfs(int s){
  int u,v;
  Enque(s);
  while(true){

    if(isEmpty()==true) {
      break;
    }
    u=Deque();
    //  cout << "u = " << u << endl;
      for(int i=1;i<= n;i++){
 
      if(us[i]==false && g[u][i] == 1){
	v=i;
	//	cout << "i - " << i <<endl;
	us[i]=true;
	d[v]=d[u]+1;
	Enque(v);
      }
    }
  }
}

int main(){

  int n2,data,u;

 //load n
  cin >>n;

  //initialize
  que.tail=0;
  que.head=0;
  for(int i=0;i<N;i++){
    us[i]=false;
    d[i]=-1;
    for(int j=0;j<N;j++){
      g[i][j]=0;
    }
  }

  //load data
  for(int i=0;i<n;i++){
    scanf("%d%d",&u,&n2);
    for(int j=0;j<n2;j++){
      scanf("%d",&data);
      g[u][data]=1;
    }
  }
  //execute

  d[1]=0;
  us[1]=true;
  bfs(1);


  //print
  for(int i=1;i<=n;i++){
    printf("%d %d\n",i,d[i]); 
  }

  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++)
		cout << i + 1 << " " << d[i] << endl;

	return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<cstdlib>
#include<string.h>
#include<stack>
#include<queue>
using namespace std;

int n;
int m[100][100], d[100], f[100];
int t = 0;
char c[100];
queue<int> q;

void bfs(int u){
  q.push(u);
  c[u] = 'g';
  d[u] = 0;

  while(q.empty() == 0){
    u = q.front();
    q.pop();
    for(int i = 0; i < n; i++){
      if(m[u][i] == 1 && c[i] == 'w'){
        q.push(i);
        c[i] = 'g';
        d[i] = d[u] + 1;
      }

    }
    c[u] = 'b';
  }

}


int main(){

  cin >> n;

  for(int i = 0; i < n; i++){
    c[i] = 'w';
    d[i] = 100;
    for(int j = 0; j < n; j++){
      m[i][j] = 0;

    }
  }

  for(int i = 0; i < n; i++){
    int id, k, x;
    cin >> id >> k;
    for(int j = 0; j < k; j++){
      cin >> x;
      m[i][x - 1] = 1;
    }
  }

  bfs(0);

  for(int i = 0; i < n; i++){
    cout << i + 1 << " " <<((c[i] == 'w') ? -1 : d[i]) << endl;
  }

  return 0;
}