Go: package main

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

//util
var sc = bufio.NewScanner(os.Stdin)

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

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func printList(list []int) {
	n := len(list)
	buf := bufio.NewWriter(os.Stdout)
	for _, v := range list[0 : n-1] {
		buf.Write([]byte(fmt.Sprintf("%d ", v)))
	}
	buf.Write([]byte(fmt.Sprintf("%d\n", list[n-1])))
	buf.Flush()
}

func max(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func min(a, b int) int {
	if a > b {
		return b
	} else {
		return a
	}
}

//solve
const INFTY = (1 << 21)
const MAX = 100
const WHITE = 0
const GRAY = 1
const BLACK = 2

var time, n int

//隣接行列
var M [MAX][MAX]int

//d[i]: 頂点1から頂点iまでの距離
var color, d [MAX]int

func bfs(s int) {
	var q []int
	q = append(q, s)
	for i := 0; i < n; i++ {
		d[i] = INFTY
	}
	//sは開始点なので、0をいれる
	d[s] = 0

	//キューが空になるまで、以下を繰り返す
	for len(q) > 0 {
		u := q[0]
		q = q[1:]
		for v := 0; v < n; v++ {
			if M[u][v] == 0 {
				continue
			}
			if d[v] != INFTY {
				continue
			}
			d[v] = d[u] + 1
			q = append(q, v)
		}
	}

	for i := 0; i < n; i++ {
		fmt.Printf("%d ", i+1)
		if d[i] == INFTY {
			fmt.Printf("%d\n", -1)
		} else {
			fmt.Printf("%d\n", d[i])
		}
	}
}

func main() {
	sc.Split(bufio.ScanWords)
	n = nextInt()
	for i := 0; i < n; i++ {
		u, k := nextInt(), nextInt()
		M[u-1][u-1] = 0

		//fmt.Println(u, k)
		if k > 0 {
			for j := 0; j < k; j++ {

				v := nextInt()
				M[u-1][v-1] = 1

			}
		}

	}

	bfs(0)

}

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

using namespace std;

#define MAX 100
#define INF 1e9

int n;
int G[MAX][MAX];
int dist[MAX];

void bfs(){
  bool used[MAX];
  fill(dist,dist+n,INF);
  fill(used,used+n,false);
  dist[0] = 0;

  queue<int> Q;
  Q.push(0);

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

    for(int i = 0 ; i < n ; i++){
      if(!used[i] && G[v][i] != INF){
	used[i] = true;
	dist[i] = dist[v] + 1;
	Q.push(i);
      }
    }
  }
}

int main(){
  cin >> n;

  fill(G[0],G[MAX],INF);
  for(int i = 0 ; i < n ; i++){
    int u,k,v;
    cin >> u >> k;
    for(int j = 0 ; j < k ; j++){
      cin >> v;
      G[u-1][v-1] = 1;
    }
  }

  bfs();

  for(int i = 0 ; i < n ; i++){
    cout << i+1 << " " << dist[i] << endl;
  }

  return 0;
}

C++: #include <bits/stdc++.h>
#define int long long
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
static const double pi = 3.141592653589793;
#define MOD 1000000007
#define INF 10000000000000


signed main(){
  int u,k,id;
  cin>>u;
  vector<vector<int> > v(u,vector<int>(0));
  rep(i,u){
    cin>>id>>k;
      rep(j,k){
        int t;cin>>t;
        v[id-1].push_back(t);
  }
}
queue<int>q;
q.push(1);
vector<int>ans(u);
rep(i,u){ans[i]=-1;}
ans[0]=0;
int f;
while(!q.empty()){
  f=q.front();
  q.pop();
  rep(i,v[f-1].size()){
    if(ans[v[f-1][i]-1]<0){
    ans[v[f-1][i]-1]=ans[f-1]+1;
    q.push(v[f-1][i]);
  }
  }
}
  rep(i,u){
    cout<<i+1<<' '<<ans[i]<<endl;
  }
}

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

int n;
vector <int> G[101];
queue <int> Q;
int  d[100];
int  dis[101];


int visit(int x){
  int t,i;
  
  Q.push(x);
  dis[x] = 0;
  d[x] = 1;

  while(Q.empty() == false) {
    
    // cout << "start Q" <<endl;

    t = Q.front();
    Q.pop();

    for(i=0; i<G[t].size();i++) {
      if(d[G[t][i]] == 0 ) {
	d[G[t][i]] = 1;
	dis[G[t][i]] = dis[t] + 1;

	Q.push(G[t][i]);
      }

    }
  }
}
    
int main() {
  
  int i,j,k,l,u,a,t;
  
  
  scanf("%d",&n);

  
  
  for(i=0;i<n;i++){
    d[i] = 0;
    dis[i] = -1;
    scanf("%d %d ",&k,&u);
    
    for(j=0;j<u;j++) {
      scanf("%d",&a);
      G[k-1].push_back(a-1);
      // printf("G[%d][%d] = 1\n",i,k-1);
    }
  }
  
  
  visit(0);

  

  for(i=0;i<n;i++) cout << i+1<<" " << dis[i] <<endl;



  return 0;

    
    
}

C++: 
#include<bits/stdc++.h>

using namespace std;

const int maxn=1e2+5;
const int inf=(1<<21);

int n,m[maxn][maxn];
int d[maxn];

void bfs(int s)
{
    queue<int>q;
    q.push(s);
    for(int i=0;i<n;i++){
        d[i]=inf;
    }
    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]!=inf){
                continue;
            }
            d[v]=d[u]+1;
            q.push(v);
        }
    }
    for(int i=0;i<n;i++){
        cout<<i+1<<" "<<((d[i]==inf)?(-1):d[i])<<endl;
    }
}

int main()
{
    scanf("%d",&n);
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            m[i][j]=0;
        }
    }
    int u,k,v;
    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;
}
/*
4
1 2 2 4
2 1 4
3 0
4 1 3
*/

C++: 
#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstdlib>
#include <cmath>
#include <vector>
#include <ctime>
#include <string>
#include <queue>

using namespace std;

const int MAX_N = 100;
int n;
int suji[MAX_N];
int	num[MAX_N];
int adj[MAX_N][MAX_N];
int ans[MAX_N][MAX_N];
int D[MAX_N];

void bfs(int src){
	queue<int> Q;
	Q.push(src);
	D[src] = 0;

	while(!Q.empty()){
		int cur = Q.front();
		Q.pop();

		for(int i = 1; i < n; i++){
			if(ans[cur][i] == 1 && D[i] == -1){
				D[i] = D[cur] + 1;
				Q.push(i);
			}
		}
	}
}


int main(void){

	cin >> n;
	for(int i = 0; i < n; i++){
		
		cin >> suji[i] >> num[i];
		D[i] = -1;
		
		for(int j = 0; j < num[i]; j++){
			cin >> adj[i][j];
			adj[i][j] -= 1;
		}
	}

	for(int i = 0; i < n; i++){
		for(int j = 0; j < n; j++){
			ans[i][j] = 0;
		}
	}

	for(int i = 0; i < n; i++){
		for(int j = 0; j < num[i]; j++){
			ans[i][adj[i][j]] = 1;
		}
	}

	bfs(0);

	for(int i = 0; i < n; i++){
		cout << i + 1 << " " << D[i] << endl;
	}
	
    return 0;
}