Go: package main

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

type vertexId int

type vertex struct {
	id vertexId
	visitedAt int
	adjs []vertexId
}

func createVertex(id int, adjsInt []int) vertex {
	adjs := make([]vertexId, len(adjsInt))
	for i := 0; i < len(adjs); i++ {
		adjs[i] = vertexId(adjsInt[i])
	}
	return vertex{
		id: vertexId(id),
		visitedAt: -1,
		adjs: adjs,
	}
}

func (v *vertex) isVisited() bool {
	return v.visitedAt >= 0
}

func bfs(id vertexId, vqueue []vertexId, vertices []vertex) {
	vertex := &vertices[id-1]
	for _, vid := range vertex.adjs {
		if !vertices[vid-1].isVisited() {
			(&vertices[vid-1]).visitedAt = vertex.visitedAt+1
			vqueue = append(vqueue, vid)
		}
	}
	if len(vqueue) > 0 {
		nextId := vqueue[0]
		nextVqueue := vqueue[1:]
		bfs(nextId, nextVqueue, vertices)
	}
}

func solveBfs(vertices []vertex) {
	vertex := &vertices[0]
	vertex.visitedAt = 0
	vqueue := make([]vertexId, 0)
	bfs(vertex.id, vqueue, vertices)
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	vertices := make([]vertex, n)
	for i := 0; i < n; i++ {
		id, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjN, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjs := make([]int, adjN)
		for j := 0; j < adjN; j++ {
			adjId, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			adjs[j] = adjId
		}
		vertices[i] = createVertex(id, adjs)
	}

	solveBfs(vertices)

	for i := 0; i < n; i++ {
		fmt.Printf("%d %d\n", vertices[i].id, vertices[i].visitedAt)
	}
}

func nextText(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

func nextInt(sc *bufio.Scanner) (int, error) {
	return strconv.Atoi(nextText(sc))
}

C++: //
//  main.cpp
//
// g++ -std=c++14 main.cpp
//

//#include "main.hpp"
#include <iostream>
#include <vector>
#include <stack>
#include <algorithm>
#include <math.h>
#include <queue>
#include <tuple>
using namespace std;
typedef long long ll;

int main(void){
    int n;
    cin >> n;
    
    vector<int> v(n, -1);
    int a[105][105] = {};
    for (int i = 0; i < n; i++) {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; j++) {
            int v;
            cin >> v;
            a[u - 1][v - 1] = true;
        }
    }
    
    queue<int> que;
    int num[105] = {}, idx = 0;
    que.push(0);
    v[0] = 0;
    num[0] = 1;
    
    bool at[105] = {};
    at[0] = true;
    while (!que.empty()) {
        int q = que.front();
        for (int j = 0; j < n; j++) {
            if (a[q][j] && !at[j]) {
                at[j] = true;
                que.push(j);
                v[j] = idx + 1;
                num[idx + 1]++;
            }
        }
        num[idx]--;
        if (!num[idx]) idx++;
        que.pop();
    }
    
    for (int i = 0; i < n; i++) cout << i + 1 << " " << v[i] << endl;
    
}
// g++ -std=c++14 main.cpp

C++: #include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cstring>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <list>
#include <utility>
#include <ctime>
#define INF 1000000000
#define LINF 9000000000000000000
#define mod 1000000007
 
#define rep(i,n) for(int i=0;i<int(n);i++)
#define rrep(i,n) for(int i=(n);i>=0;i--)
#define REP(i,a,b) for(int i=(a);i<int(b);i++)
#define all(x) (x).begin(),x.end()
#define vector_rsort(x) sort(all(x));reverse(all(x))
#define array_rsort(x,n) sort(x,x+n);reverse(x,x+n);
#define pb push_back
#define mp make_pair
#define MOD(x) (x%(mod))

#define Yes cout<<"Yes"<<endl
#define YES cout<<"YES"<<endl
#define No cout<<"No"<<endl
#define NO cout<<"NO"<<endl
using namespace std;
 
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef pair<int,int> pi;
 
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};
bool debug=false;
/*---------------------------------------------------*/

int n,u,k,v;
int g[105][105];

void init(){
  rep(i,105){
    rep(j,105){
      g[i][j]=INF;
    }
  }
}

void wf(){
  rep(k,105){
    rep(i,105){
      rep(j,105){
	g[i][j]=min(g[i][j],g[i][k]+g[k][j]);
      }
    }
  }
}

int main(){
  init();
  cin>>n;
  rep(i,n){
    cin>>u>>k;
    rep(i,k){
      cin>>v;
      g[u][v]=1;
    }
  }
  wf();
  for(int i=1;i<=n;i++){
    if(g[1][i]==INF)cout<<i<<" "<<0<<endl;
    else cout<<i<<" "<<g[1][i]<<endl;
  }
  return 0;
}

C++: #include <iostream>
#include <vector>
#include <map>
#include <algorithm>
#include <set>
#include <queue>
using namespace std;

int main(void){
  int N;
  cin >> N;
  
  vector<vector<int>> G(N);
  for(int i=0;i<N;i++){
    int u,k;
    cin >> u >> k;
    for(int j=0;j<k;j++){
      int tmp;
      cin >> tmp;
      G[i].push_back(tmp-1);
    }
  }
  
  vector<int> S(N);
  for(int i=0;i<N;i++){
    S[i] = -1;
  }
  queue<pair<int,int>> Q;
  for(auto it:G[0]){
    Q.push(make_pair(it,1));
  }
  S[0] = 0;
  while(!Q.empty()) {
    auto i = Q.front();
    Q.pop();
    if(S[i.first]>-1){
      continue;
    } else {
      S[i.first] = i.second;
    }
      
    for(auto it: G[i.first]){
      Q.push(make_pair(it,i.second+1));
    }
  }
  
  for(int i=0;i<N;i++){
    cout << i+1 << " " << S[i] << endl;
  }
}

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 <queue>
using namespace std;

int n;
bool A[105][105];
int D[105];

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<105; dst++){
            if(A[cur][dst]==1 && D[dst]==-1){
                D[dst]=D[cur]+1;
                Q.push(dst);
            }
        }
        
    }
}

int main(int argc, const char * argv[]) {
    for(int i=0; i<105; i++){
        for(int j=0; j<105; j++){
            A[i][j] = 0;
        }
    }
    cin >> n;
    for(int i=0; i<n; i++){
        int u;
        int k;
        cin >> u >> k;
        u--;
        for(int j=0; j<k; j++){
            int v;
            cin >> v;
            v--;
            A[u][v] = 1;
        }
    }
    for(int i=0; i<105; i++){
        D[i] = -1;
    }
    bfs(0);
    for(int i=0; i<n; i++){
        cout << i+1 << " " << D[i] << endl;
    }
    return 0;
}