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 <stdio.h>
#include <iostream>
#include <utility>
#include <algorithm>
#include <math.h>
#include <vector>
#include <list>
#define inf 200
using namespace std;

int n;
list<int> adj[101];
int d[101];
bool f[101];
void BFS(int v)
{
    int m = 0;
    f[v] = false;
    while (!adj[v].empty())
    {
        d[adj[v].front()] = min(d[v] + 1, d[adj[v].front()]);
        adj[v].pop_front();
    }
    for (int i = 1; i <= n; i++)
    {
        if (f[i] && d[i] < d[m])
            m = i;
    }
    if (m > 0)
        BFS(m);
}

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

int main()
{
    int u, k, v;
    cin >> n;
    for (int i = 0; i <= n; i++)
    {
        d[i] = inf;
        f[i] = true;
    }
    for (int i = 0; i < n; i++)
    {
        cin >> u >> k;
        while (k > 0)
        {
            cin >> v;
            adj[u].push_back(v);
            k--;
        }
    }
    d[1] = 0;
    BFS(1);

    print();

    return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<queue>
using namespace std;
const int INF=(1<<21);
int n,M[101][101];
int d[101]; //最短距離を記録(到達不可な時はINF)
void bfs(int s){
  queue<int>q;
  q.push(s);//始点sをいれる(訪問)
  for(int i=0;i<n;i++) d[i]=INF;
  d[s]=0;
  while(!q.empty()){
    int u=q.front();
    q.pop();
    for(int v=0;v<n;v++){
      if(M[u][v]==0) continue; //辺がない
      if(d[v]!=INF) continue; //訪問したことがある
      d[v]=d[u]+1; //vは未訪問の頂点であり、隣接しているためd[u]に1を足す
      q.push(v); //vを始点に
    }
  }
  for(int i=0;i<n;i++){
    cout<<i+1<<" "<<( (d[i]==INF)?(-1):d[i] )<<endl;
  } //到達不可能か
}
int main(){
  int u,k,v;
  scanf("%d",&n);
  for(int i=0;i<n;i++){
    scanf("%d%d",&u,&k);
    u--;
    for(int j=0;j<k;j++){
      scanf("%d",&v);
      v--;
      M[u][v]=1;
    }
  }
  bfs(0);
  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

using ll = long long;
#define REP(i, n) for(int (i)=0; (i)< (n); ++i)
#define REPR(i, n) for(int (i)=(n); (i)>=0; --i)
#define FOR(i, n, m) for(int (i)=(n); (i)<(m); ++i)


int main(){
  int n;
  cin >> n;
  vector<vector<int>> g(n);
  REP(i, n){
    int id, k;
    cin >> id >> k;
    g[i].resize(k);
    REP(j, k){
      int v;
      cin >> v;
      v--;
      g[i].push_back(v);
    }
  }
  vector<int> dist(n, -1);
  dist[0] = 0;
  queue<pair<int, int>> que;
  que.push({0,0});
  while(!que.empty()){
    int v, d;
    tie(v, d) = que.front();que.pop();
    REP(i, g[v].size()){
      int nv = g[v][i];
      if(dist[nv] != -1) continue;
      dist[nv] = d + 1;
      que.push({nv, d+1});
    }
  }
  REP(i, n){
    cout << i+1 << " " << dist[i] << endl;
  }
  return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <vector>
#include <deque>
#include <queue>
#include <list>
#include <stack>
#include <string>
#include <tuple>
#include <functional>
#include <numeric>
#include <cmath>
#include <iomanip>
#include <map>
#include <random>
#include <cstdlib>
#define Loop(i, n) for(int i = 0; i < (int)n; i++)
#define Loop1(i, n) for(int i = 1; i <= (int)n; i++)
#define Loopr(i, n) for(int i = (int)n - 1; i >= 0; i--)
#define Loopr1(i, n) for(int i = (int)n; i >= 1; i--)
using namespace std;
typedef long long int ll;

vector<int> V[105];
queue<int> Q;
vector<int> color(105, 1), d(105, 0);

int main() {
	int n;
	cin >> n;
	Loop(i, n) {
		int u, k;
		cin >> u >> k;
		Loop(j, k) {
			int v;
			cin >> v;
			V[u].push_back(v);
		}
	}
	//
	Q.push(1);
	color[1] = 2;
	while (Q.size() > 0) {
		int u = Q.front();
		Q.pop();
		Loop(i, V[u].size()) {
			if (color[V[u][i]] == 1) {
				Q.push(V[u][i]);
				color[V[u][i]] = 2;
				d[V[u][i]] = d[u] + 1;
			}
		}
	}
	Loop1(i, n) {
		cout << i << " " << d[i] << endl;
	}
	return 0;
}

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

int n;
vector< vector<int> > G;
vector<int> color;
vector<int> dis;

void Bfs(int start) {
  queue<int> q;
  q.push(start);
  color[start]++;
  dis[start] = 0;

  while (q.empty() == false) {
    int u = q.front();
    q.pop();
    for (int v = 0; v < n; v++) {
      if (G[u][v] == 1 && color[v] == 0) {
        color[v]++;
        dis[v] = dis[u] + 1;
        q.push(v);
      }
    }
    color[u]++;
  }
}

int main() {
  cin >> n;
  G.resize(n, vector<int>(n));
  color.resize(n);
  dis.resize(n, -1);
  for (int i = 0; i < n; i++) {
    int u, k;
    cin >> u >> k;
    u--;
    for (int j = 0; j < k; j++) {
      int v;
      cin >> v;
      v--;
      G[u][v]++;
    }
  }

  Bfs(0);

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

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

const int nIMPOS = -1;
struct StDist
{
  int m_nDist;
  int m_nDmy;

  StDist(int nDist) : m_nDist(nDist), m_nDmy(0)
  { }
};

void fnInput(vector<vector<int>>& rvvnAdjcy, vector<StDist>& rvoDist)
{
  int nxSiz;
  cin >> nxSiz;

  rvvnAdjcy.resize(nxSiz + 1, vector<int>(nxSiz + 1, 0));
  for (int i = 0; i < nxSiz; ++i)
  {
    int nx, nySiz;
    cin >> nx >> nySiz;
    for (int j = 0; j < nySiz; ++j)
    {
      int ny;
      cin >> ny;
      rvvnAdjcy[nx][ny] = 1;
    }
  }
  StDist oDist(nIMPOS);
  rvoDist.resize(nxSiz + 1, oDist);
}

void fnBreadthFirstSearch(const vector<vector<int>>& cnrvvnAdjcy, 
                          queue<int>& rqnBFSrch, vector<StDist>& rvoDist)
{
  while (rqnBFSrch.size())
  {
    int nx = rqnBFSrch.front(); rqnBFSrch.pop();
    for (int ny = 1; ny < cnrvvnAdjcy[nx].size(); ++ny)
    {
      if (!cnrvvnAdjcy[nx][ny])          continue;
      if (rvoDist[ny].m_nDist != nIMPOS) continue; 

      int nDist = rvoDist[nx].m_nDist + 1;
      rvoDist[ny].m_nDist = nDist;
      rqnBFSrch.push(ny);
    }
  }
}

void fnResult(const vector<StDist>& cnrvoDist)
{
  for (int i = 1; i < cnrvoDist.size(); ++i)
    cout << i <<  " " << cnrvoDist[i].m_nDist << endl;
}

int main()
{
  cin.tie(0);
  ios::sync_with_stdio(false);
  vector<vector<int>> vvnAdjcy;
  queue<int>  qnBFSrch;
  vector<StDist> voDist;

  fnInput(vvnAdjcy, voDist);

  voDist[1].m_nDist = 0;
  qnBFSrch.push(1);
  fnBreadthFirstSearch(vvnAdjcy, qnBFSrch, voDist);
  fnResult(voDist);

  return 0;
}