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++: #include <set>
#include <map>
#include <list>
#include <queue>
#include <stack>
#include <cmath>
#include <ctype.h>
#include <ctime>
#include <cstdio>
#include <vector>
#include <string>
#include <bitset>
#include <cctype>
#include <cstdlib>
#include <cstring>
#include <utility>
#include <numeric>
#include <complex>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <cassert>
#include <iostream>
#include <iterator>
#include <algorithm>

using namespace std;
#define N 100
#define INF 1e9

queue<int> Q;
int n,M[N][N];
int dist[N];

void bsf(int l){
	Q.push(l);
	for(int i = 0;i < n;i++) dist[i] = INF;

	dist[l]=0;
	while(!Q.empty()){
		int u = Q.front();
		Q.pop();
		for(int i=0;i<n;i++){
			if(M[u][i] == 0)continue;
			if(dist[i] != INF)continue;
			dist[i] = dist[u] + 1;
			Q.push(i);
		}
	}
}

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;
		}
	}
	bsf(0);
	return 0;
}

C++: #include <iostream>
#include <string>
#include <cstring>
#include <fstream>
#include <cmath>
#include <iomanip>
#include <cstdlib>
#include <algorithm>
#include <vector>
#include <map>
#include <deque>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <list>
#include <unordered_map>

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);

}

C++: #include <iostream>
#include <vector>
#include <stack>
#include <queue>
#include <cmath>
#include <algorithm>
using namespace std;

void solve(){
  int n; cin >> n;
  vector<vector<int> > v(n + 1, vector<int>(n + 1, 0));
  for(int i = 0; i < n; i++){
    int u, k; cin >> u >> k;
    for(int j = 0; j < k; j++){
      int x; cin >> x;
      v[u][x] = 1;
    }
  }
  queue<int> q;
  vector<int> ans(n + 1, -1), c(n + 1, 0);
  q.push(1);
  ans[1] = 0;
  c[1] = 1;
  while(q.size() != 0){
    int x = q.front();
    q.pop();
    for(int i = 1; i <= n; i++){
      if(v[x][i] == 1 && c[i] == 0){
        q.push(i);
        ans[i] = ans[x] + 1;
        c[i] = 1;
      }
    }
  }
  for(int i = 1; i <= n; i++){
    cout << i << " " << ans[i] << endl;
  }
  return;
}

int main(){
  solve();
  return 0;
}

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];

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];
    }
  }

   int h;
  for(int i=0;i<n;i++){
    int Min = i;
    for(int j=i;j<n;j++){
      if(u[Min] > u[j])Min = j; 
    }
    h = u[Min];
    u[Min] = u[i];
    u[i] = h;
  }

  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]);//cout << "push!= " << imap[p][i] << endl;
	used[imap[p][i]] = true;
	ans[imap[p][i]] = ans[p] + 1;
      }
    }
  }
  //for(int i=0;i<n;i++)cout << u[i] << endl;
 
  for(int i=0;i<n;i++){
    cout << u[i]-1 << " " << ans[u[i]] << endl;
  }

  return 0;
}

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

#define FOR(i,k,n) for (int (i)=(k); (i)<(n); ++(i))
#define REP(i,n) FOR(i,0,n)
using namespace std;

int main(){
    int n,u,k,v,src=0;
    cin >> n;
    int D[n],g[n][n];
    REP(i,n){
        D[i] = 0;
        REP(j,n){
            g[i][j] = 0;
        }    
    }
    REP(i,n){ 
        cin >> u >> k;
            REP(j,k){
                cin >> v;
                g[v-1][u-1] = 1;
            }
    }

    queue<int> Q;
    Q.push(src);
    while (!Q.empty()) {
        int cur = Q.front();
        Q.pop();
            REP(i,n){
                if(g[i][cur] == 1 && D[i] == 0){
                    D[i] = D[cur] + 1;
                    Q.push(i);
                }
            }
    }

    REP(i,n){
        cout << i+1 << " " << D[i] << endl;    
    }
}