Go: package main

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

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

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

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
type Queue struct {
	arr []int
}

func (q *Queue) push(v int) {
	q.arr = append(q.arr, v)
}

func (q *Queue) pop() int {
	res := q.arr[0]
	q.arr = q.arr[1:]
	return res
}

func (q *Queue) isEmpty() bool {
	return len(q.arr) == 0
}

func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	G := make([][]int, N)
	for i := 0; i < N; i++ {
		u, k := sc.nextInt()-1, sc.nextInt()
		for j := 0; j < k; j++ {
			G[u] = append(G[u], sc.nextInt()-1)
		}
	}
	var q Queue
	seen := make([]int, N)
	for i := 0; i < N; i++ {
		seen[i] = -1
	}
	var search func(cur int)
	search = func(cur int) {
		for i := 0; i < len(G[cur]); i++ {
			next := G[cur][i]
			if seen[next] == -1 {
				q.push(next)
				seen[next] = seen[cur] + 1
			}
		}
	}
	q.push(0)
	seen[0] = 0
	for !q.isEmpty() {
		search(q.pop())
	}

	for i := 0; i < N; i++ {
		fmt.Fprintln(wtr, i+1, seen[i])
	}
	wtr.Flush()
}

C++: #include<bits/stdc++.h>
#include<string>
#include<cctype>
#include<cmath>
#include<queue> 
#define rep(i,n) for(int i=0;i<(n);i++)
using namespace std;
 
int main(){
  queue <int> q1;
  int n,i,j;
  cin >> n;
  int d[n][n];
  rep(i,n){
    rep(j,n){
      if(i==j){
        d[i][j]=0;
      }else{
       d[i][j]=100000;
      }
    }
  }
  rep(i,n){
    int u,k;
    cin >> u >> k;
    q1.push(u);
    if(k>0){
     int v[k];
     rep(j,k){
       cin >> v[j];
       q1.push(v[j]);
     }
     int f = q1.front()-1;
     q1.pop();
     rep(i,k){
       int e=q1.front()-1;
       d[f][e]=1;
       q1.pop();
     }
    }else{
     q1.pop();
    }
  }

  rep(i,n){
    for(j=2;j<n;j++){
    d[0][i]=min(d[0][i],d[0][j]+d[j][i]);
    }
  }
 
 rep(i,n){
   cout << i+1 << ' ' <<d[0][i] << endl;
 }
 
  return 0;
}

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

int main() {
    // 頂点数と辺数
    int N; cin >> N ;

    // グラフ入力受取 (ここでは無向グラフを想定)
    Graph G(N);
    for (int i = 0; i < N; ++i) {
        int a , b;
        cin >> a >> b;
        a = a - 1;
        if(b != 0){
        for(int j = 0; j < b; j++){
            int e1;
            cin >> e1;

            e1 = e1 - 1;
        //    G[e1].push_back(a);
            G[a].push_back(e1);
        }
        }

    }

    // BFS のためのデータ構造
    vector<int> dist(N, -1); // 全頂点を「未訪問」に初期化
    queue<int> que;

    // 初期条件 (頂点 0 を初期ノードとする)
    dist[0] = 0;
    que.push(0); // 0 を橙色頂点にする

    // BFS 開始 (キューが空になるまで探索を行う)
    while (!que.empty()) {
        int v = que.front(); // キューから先頭頂点を取り出す
        que.pop();

        // v から辿れる頂点をすべて調べる
        for (int nv : G[v]) {
            if (dist[nv] != -1) continue; // すでに発見済みの頂点は探索しない
            // 新たな白色頂点 nv について距離情報を更新してキューに追加する
            dist[nv] = dist[v] + 1;
            que.push(nv);
        }
    }

    // 結果出力 (各頂点の頂点 0 からの距離を見る)
    for (int v = 1; v <= N; ++v) cout << v << " " << dist[v - 1] << endl;
}

C++: #include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<int, int>;

#define rep(i, n) for (int i = 0; i < n; ++i)
#pragma region Debug
template <typename T>
void view(const std::vector<T> &v)
{
    for (const auto &e : v)
    {
        std::cout << e << " ";
    }
    std::cout << std::endl;
}
template <typename T>
void view(const std::vector<std::vector<T>> &vv)
{
    for (const auto &v : vv)
    {
        view(v);
    }
}
#pragma endregion

int main()
{
    int n;
    cin >> n;
    vector<vector<int>> g(n, vector<int>());
    vector<int> d(n, -1);

    rep(i, n)
    {
        int k;
        cin >> k >> k;
        rep(j, k)
        {
            int t;
            cin >> t;
            t--;
            g[i].emplace_back(t);
        }
    }

    queue<int> q;
    q.push(0);
    d[0] = 0;
    while (q.size())
    {
        int v = q.front();
        q.pop();

        for (auto nv : g[v])
        {
            if (d[nv] >= 0)
                continue;

            d[nv] = d[v] + 1;
            q.push(nv);
        }
        // cout << v << " " << q.size() << endl;
    }

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

    return 0;
}

C++: /*
http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_11_C&lang=ja
*/

#include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (n); ++i)
using namespace std;
using ll = long long;
using P = pair<int,int>;

int main(){
    int n;
    cin >> n;
    vector<vector<int>> to(n);
    rep(i,n){
        int u,k;
        cin >> u >> k;
        rep(j,k){
            int v;
            cin >> v;
            v--;
            to[i].push_back(v);
        }
    }

    vector<int> dist(n,-1);
    queue<int> q;
    dist[0]=0;
    q.push(0);

    while(!q.empty()){
        int p;
        p = q.front();
        q.pop();
        //cout << "p" << p << endl;
        rep(i,to[p].size()){
            if(dist[to[p][i]]==-1){
                dist[to[p][i]]=dist[p]+1;
                q.push(to[p][i]);
            }
        }
    }

    rep(i,dist.size()){
        cout << i+1 <<" " <<dist[i] << endl;
    }
}

C++: #include<bits/stdc++.h>
using namespace std;
const int maxn=100+10;
int n,dis[maxn],vis[maxn];
vector<int>G[maxn];
void bfs(){
    memset(dis,0,sizeof dis);
    memset(vis,0,sizeof vis);
    queue<int>que;
    que.push(1);vis[1]=1;dis[1]=0;
    while(!que.empty()){
        int cur=que.front();que.pop();
        for(auto i:G[cur]){
            if(!vis[i]){
                que.push(i);
                dis[i]=dis[cur]+1;
                vis[i]=1;
            }
        }
    }
}
int main()
{
    cin>>n;
    for(int i=0;i<n;i++){
        int u,k;cin>>u>>k;
        for(int j=0;j<k;j++){
            int v;cin>>v;
            G[u].push_back(v);
        }
    }
    bfs();
    for(int i=1;i<=n;i++) if(!vis[i]) dis[i]=-1;//在bfs完以后还没到达的点到1点的距离设置为-1
    for(int i=1;i<=n;i++) cout<<i<<" "<<dis[i]<<"\n";
}
/*
4
1 2 2 4
2 1 4
3 0
4 1 3
*/