Go: package main

import (
	"fmt"
	"os"
	"bufio"
	"strconv"
	"container/list"
)

const MaxNode int = 100

var d []int
var A [][]int
var N int
var l *list.List

func bfs(u int) {
	d[u] = 0
	l.PushBack(u)
	for ;l.Len() != 0; {
		u = l.Front().Value.(int)
		l.Remove(l.Front())
		for v:=0; v<N; v++ {
			if A[u][v] == 0 {
				continue
			}
			if d[v] != -1 {
				continue
			}
			d[v] = d[u] + 1
			l.PushBack(v)
		}
	}
}


func nextInt(scanner *bufio.Scanner) int {
	scanner.Scan()
	num, _ := strconv.Atoi(scanner.Text())
	return num
}

func print() {
	for i:=0; i<N; i++ {
		fmt.Printf("%d %d\n", i+1, d[i])
	}
}

func initVariable() {
	d = make([]int, MaxNode)
	A = make([][]int, MaxNode)
	l = list.New()
	for i:=0; i<MaxNode; i++ {
		A[i] = make([]int, MaxNode)
		d[i] = -1
	}
}


func main() {
	initVariable()
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	N = nextInt(scanner)
	for i:=0; i<N; i++ {
		idx := nextInt(scanner)
		cnt := nextInt(scanner)
		for j:=0; j<cnt; j++ {
			node := nextInt(scanner)
			A[idx-1][node-1] = 1 
		}
	}
	bfs(0)
	print()
}

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

enum Status {WHITE, GRAY, BLACK};

queue<int> que;
Status *status;
int *dist;
vector<vector<int> > a;
int n;

int main(){
        cin>>n;
        a = vector<vector<int> >(n, vector<int>());
        status = new Status[n];
        dist = new int[n];

        int m, k, r;
        for(int i=0;i<n;i++){
                cin>>r;
                cin>>m;
                for(int j=0;j<m;j++){
                        cin>>k;
                        a[r-1].emplace_back(k-1);
                }
        }
        for(int i=0;i<n;i++) status[i] = WHITE;
        for(int i=0;i<n;i++) dist[i] = -1;

        que.push(0);
        dist[0] = 0;
        while(!que.empty()){
                int v = que.front(); que.pop();
                if(status[v]==BLACK) continue;
                for(int i=0;i<a[v].size();i++){
                        if(status[a[v][i]]==WHITE){
                                dist[a[v][i]] = dist[v]+1;
                                status[a[v][i]] = GRAY;
                                que.push(a[v][i]);
                        }
                }
                status[v] = BLACK;
        }

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

C++: //#define LOCAL

#include<bits/stdc++.h>

using namespace std;

#define rep(a, b) for(int i = a; i <= b; i++)
#define mst(a) memset(a, 0, sizeof(a))

const int MAX = 1e2 + 10;


bool mtx[MAX][MAX];
int vis[MAX];
int n;

queue<int> q;

void init(void)
{
	while(!q.empty())
		q.pop();
	mst(vis);
	mst(mtx);
	n = 0;
	return;
}

bool check(int x, int y)
{
	if(mtx[x][y] && !vis[y])
		return true;
	return false;
}

void GetAns(void)
{
	rep(2, n)
	{
		if(vis[i] == 0)
			vis[i] = -1;
	}
	return;
}

void Bfs(void)
{
	q.push(1);
	while(!q.empty())
	{
		int cur = q.front();
		q.pop();
		rep(1, MAX - 10)
		{
			if(check(cur, i))
			{
				q.push(i);
				vis[i] = vis[cur] + 1;
			}
		}
	}
	return;
}

int main()
{
/*#ifdef LOCAL
	freopen("in.txt", "r", stdin);
#endif*/

	while(~scanf("%d", &n))
	{
		rep(1, n)
		{
			int row;
			scanf("%d", &row);
			int num;
			scanf("%d", &num);
			for(int j = 1; j <= num; j++)
			{
				int tmp;
				scanf("%d", &tmp);
				mtx[row][tmp] = true;
			}
		}
		
		Bfs();

		GetAns();
		
		rep(1, n)
			printf("%d %d\n", i, vis[i]);
	}
	return 0;
}

C++: #include<iostream>
#include<queue>
 
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);
    int i, u, v;
    for ( i = 0; i < n; i++ ) d[i] = INFTY;
    d[s] = 0;
 
    while ( !q.empty() ) {
        u = q.front();
        q.pop();
        for ( 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 ( i = 0; i < n; i++ ) {
            cout << i+1 << " " << ( (d[i] == INFTY) ? (-1) : d[i] ) << endl;
    }
}
 
int main() {
    int u, k, v, i, j;
 
    cin >> n;
 
    for ( i = 0; i < n; i++ ) {
        for ( j = 0; j < n; j++ ) M[i][j] = 0;
    }
 
    for ( i = 0; i < n; i++ ) {
        cin >> u >> k;
        u--;
        for ( j = 0; j < k; j++ ) {
            cin >> v;
            v--;
            M[u][v] = 1;
        }
    }
 
    bfs(0);
 
    return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <complex>
#include <stack>
#include <queue>
#include <list>
#include <utility>
#include <set>
using namespace std;

int main(){
    int n;
    cin >> n;
    int g[110][110];
    int i, j;
    int u, k, v;
    int dist[110];
    bool visited[110];
    
    for(i = 0; i < n; i++){
        dist[i] = -1;
        for(j = 0; j < n; j++){
            g[i][j] = 0;
        }
    }
    
    for(i = 0; i < n; i++){
        cin >> u >> k;
        u--;
        for(j = 0; j < k; j++){
            cin >> v;
            v--;
            g[u][v] = 1;
        }
    }
    
    queue<int> q1, q2;
    q1.push(0);
    
    for(i = 0; q1.size(); i++){
        while(!q1.empty()){
            int p = q1.front();
            q1.pop();
            
            if(visited[p]) continue;
            visited[p] = true;
            
            dist[p] = i;
            
            for(j = 0; j < n; j++){
                if(g[p][j]){
                    q2.push(j);
                }
            }
        }
        q1 = q2;
        q2 = queue<int>();
    }
    
    for(i = 0; i < n; i++){
        cout << i+1 << " " << dist[i] << endl;
    }
}

C++: #include <iostream>
#include <iomanip>
#include <string>
#include <stack>
#include <vector>
#include <math.h>
#include <stdio.h>
#include <algorithm>
#include <utility>
#include <functional>
#include <map>
#include <set>
#include <queue>
#include <list>
using namespace std;
using pii  = pair<int,int>;
using ll=long long;
using ld=long double;
#define pb push_back
#define mp make_pair
#define rep(i,n) for(int i=0;i<(n);++i)
#define REP(i,a,b) for(int i=(a);i<(b);++i)
#define crep(i) for(char i='a';i<='z';++i)
#define psortsecond(A,N) sort(A,A+N,[](const pii &a, const pii &b){return a.second<b.second;});
#define ALL(x) (x).begin(),(x).end()
#define endl '\n'
int ctoi(const char c){
  if('0' <= c && c <= '9') return (c-'0');
  return -1;
}
long long gcd(long long a, long long b){return (b == 0 ? a : gcd(b, a%b));}
long long lcm(long long a, long long b){return a*b/gcd(a,b);}
constexpr ll MOD=1000000007;
constexpr ld EPS=10e-8;
template<typename T> istream& operator>>(istream& is,vector<T>& v){for(auto&& x:v)is >> x;return is;}
template<typename T,typename U> istream& operator>>(istream& is, pair<T,U>& p){ is >> p.first; is >> p.second; return is;}
template<typename T,typename U> ostream& operator>>(ostream& os, const pair<T,U>& p){ os << p.first << ' ' << p.second; return os;}
template<class T> ostream& operator<<(ostream& os, vector<T>& v){
    for(auto i=begin(v); i != end(v); ++i){
        if(i !=begin(v)) os << ' ';
        os << *i;
    }
    return os;
}

queue<pair<ll,ll>> Q;
vector<vector<ll>> V(107);
ll chek[107];
ll ans[107];

int main(){
    ll N;
    cin >> N;
    ll A,B,C;
    rep(i,N){
        cin >> A >> B;
        rep(j,B){
            cin >> C;
            V[A].pb(C);
        }
    }
    rep(i,N+1){
        ans[i]=-1;
    }
    Q.push(mp(1,0));
    chek[1]=1;
    while(Q.size()>0){
        rep(i,V[Q.front().first].size()){
            if(chek[V[Q.front().first][i]]==0){
                Q.push(mp(V[Q.front().first][i],Q.front().second+1));
                chek[V[Q.front().first][i]]=1;
            }
        }
        ans[Q.front().first]=Q.front().second;
        Q.pop();
    }
    REP(i,1,N+1){
        cout << i << " " << ans[i] << endl;
    }
}