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

#define rep(i, n) REP(i, 0, n)
#define ALL(v) v.begin(), v.end()
#define MSG(a) cout << #a << " " << a << endl;
#define REP(i, x, n) for (int i = x; i < n; i++)
#define OP(m) cout << m << endl
typedef long long ll;
typedef unsigned long long ull;

int m[100][100];
int d[100];
int n;
const int INF = 1e8;

void bfs(int u)
{
    queue<int> q;
    q.push(u);

    d[u] = 0;

    while (!q.empty())
    {
        int t = q.front();
        q.pop();

        rep(i, n)
        {
            if (m[t][i] == 0 || d[i] != INF)
                continue;
            d[i] = d[t] + 1;
            q.push(i);
        }
    }
}

int main()
{
    cin >> n;
    rep(i, n) d[i] = INF;

    rep(i, n) rep(j, n) m[i][j] = 0;

    rep(i, n)
    {
        int u, k;
        cin >> u >> k;
        --u;
        rep(j, k)
        {
            int v;
            cin >> v;
            m[u][--v] = 1;
        }
    }

    bfs(0);

    rep(i, n)
    {
        if (d[i] == INF)
            cout << i + 1 << " " << -1 << endl;
        else
            cout << i + 1 << " " << d[i] << endl;
    }

    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
static const int N=100;
enum COLOR{WHITE,GRAY,BLACK};
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,v,k,i,j;
    scanf("%d",&n);
    for(i=0;i<n;i++)
    {
        for(j=0;j<n;j++)M[i][j]=0;
    }

    for(i=0;i<n;i++)
    {
        scanf("%d %d",&u,&k);
        u--;
        for(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;

#define int long long
 	
const int N = 100 + 1;
vector< int > g[N];
int d[N]; // stores the depth of all nodes

void BFS(int u){
   queue<int> q;
   q.push(u);
   d[u] = 0;
   while (!q.empty()){
	   int x = q.front(); q.pop();
	   for(auto it : g[x]){
		     if (d[it] != -1) continue;
		     d[it] = d[x] + 1;
		     q.push(it);
		 }  
	 }
}

int32_t main(){
   int n, m, deg;
   cin >> n;
   for (int i = 0; i < n; i++){
	    cin >> m >> deg;
	    m--;
	    for(int i = 0; i < deg; i++){
		    int x;
		    cin >> x;
		    x--;
		    g[m].push_back(x);
	    }  
	 }
	for (int i = 0; i < n; i++) d[i] = -1;
    BFS(0);
    for (int i = 0; i < n; i++){
	   int idx = i + 1;
	   if (d[i] == -1) cout << idx << " " << -1 << endl;
	   else cout << idx << " " << d[i] << endl; 
	 }
}

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

#define MAX_NODE 10000
#define INF 1000000000

using namespace std;

int d[MAX_NODE];
vector<int> adj[MAX_NODE];

int bfs(int n, int start){
	queue<int> que;
	for(int i=0;i<n;i++){
		d[i]=(i==start)?0:INF;
	}
	que.push(start);
	while(que.empty()==0){
		int from=que.front();
		que.pop();
		for(int i=0;i<adj[from].size();i++){
			int to=adj[from][i];
			if(d[to]==INF){
				d[to]=d[from]+1;
				que.push(to);
			}
		}
	}
}	

int main(){
	int n,u,k,v;
	cin>>n;
	for(int i=0;i<n;i++){
		cin>>u>>k;
		for(int j=0;j<k;j++){
			cin>>v;
			v--;
			adj[u-1].push_back(v);
		}
	}
	cout<<adj[0].size()<<endl;
	bfs(n,0);
	for(int i=0;i<n;i++){
		cout<<i+1<<" "<<d[i]<<endl;
	}
	return 0;
}

C++: #include <queue>
#include <vector>
#include <iostream>
using namespace std;
int N;
int D[110];
int G[110][110];
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=0;i<N;i++){
			if(G[cur][i] && D[i]==0){
				D[i] = D[cur]+1;
				Q.push(i);
			}
		}
	}
	for(int i=0;i<N;i++){
		if(i!=src && D[i]==0) D[i]=-1;
	}
	D[src]=0;
}

int main(){
	while(cin >> N && N>0){
		vector<vector<int> > g(110,vector<int>(110,0));
		int u,k;
		for(int i=0;i<N;i++){
			cin >> u >> k;
			for(int j=0;j<k;j++){
				int a;
				cin >> a;
				g[u-1].push_back(a); 
			}
		}
		for(int i=0;i<N;i++){
			for(int j=0;j<g[i].size();j++){
				int f = g[i][j];
				G[i][f-1] = 1;
			}
		}
		bfs(0);
		for(int i=0;i<N;i++){
			cout << i+1 << " " << D[i] << endl;
		}
	}
}

#if 0
無限ループに陥らないようにするのに少し苦労した。プログラム上では番号を0から始めたのもよくないかもしれない。
#endif