Go: package main

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

func main() {
	scn := bufio.NewScanner(os.Stdin)
	scn.Split(bufio.ScanWords)
	nextInt := func() int { scn.Scan(); r, _ := strconv.Atoi(scn.Text()); return r }
	w := bufio.NewWriter(os.Stdout)

	n := nextInt()
	vecs := make([][]int, n)
	for i := 0; i < n; i++ {
		u := nextInt()
		k := nextInt()
		for j := 0; j < k; j++ {
			vecs[u-1] = append(vecs[u-1], nextInt()-1)
		}
	}

	ds := make([]int, 0, n)
	for i := 0; i < n; i++ {
		ds = append(ds, -1)
	}

	q := make([]int, 0, n)
	q = append(q, 0)
	ds[0] = 0

	for len(q) > 0 {
		i := pop(&q)
		for _, v := range vecs[i] {
			if ds[v] == -1 {
				ds[v] = ds[i]+1
				q = append(q, v)
			}
		}
	}

	for i, d := range ds {
		fmt.Fprintln(w, i+1, d)
	}

	w.Flush()
}

func pop(q *[]int) int {
	v := (*q)[0]
	*q = (*q)[1:]
	return v
}

C++: #include<bits/stdc++.h>
using namespace std;
#define int long long
signed main(){
  int n;
  cin>>n;
  vector<vector<int> > G(n,vector<int>());
  for(int i=0;i<n;i++){
    int u,k;
    cin>>u>>k;
    u--;
    for(int j=0;j<k;j++){
      int c;
      cin>>c;
      c--;
      G[u].push_back(c);
    }
  }
  int d[n];
  memset(d,-1,sizeof(d));
  queue<int> q;
  d[0]=0;
  q.push(0);
  while(!q.empty()){
    int v=q.front();q.pop();
    for(int u:G[v]){
      if(d[u]<0){
	d[u]=d[v]+1;	
	q.push(u);
      }
    }
  }
  for(int i=0;i<n;i++) cout<<i+1<<" "<<d[i]<<endl;;
  return 0;
}

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

const long N = 100;
const long INFTY = (1<<21);

long n, M[N + 1][N + 1];
long d[N + 1];

void bfs(long s){
	queue<long> q;
	q.push(s);
	for (long i = 1; i <= n; i++) d[i] = INFTY;
	d[s] = 0;
	long u;
	while (!q.empty()){
		u = q.front();
		q.pop();
		for (long v = 1; v <= n; v++){
			if (M[u][v] == 0) continue;
			if (d[v] != INFTY) continue;
			d[v] = d[u] + 1;
			q.push(v);
		}
	}
	for (long i = 1; i <= n; i++){
		cout << i << " " << ((d[i] == INFTY) ? (-1) : d[i]) << endl;
	}
}

int main(){
	long u, k, v;
	cin >> n;
	for (long i = 1; i <= n; i++){
		for (long j = 1; j <= n; j++){
			M[i][j] = 0;
		}
	}
	for (long i = 0; i < n; i++){
		cin >> u >> k;
		for (long j = 0; j < n; j++){
			cin >> v;
			M[u][v] = 1;
		}
	}

	bfs(0);

	return 0;
}

C++: #include<iostream>
#include<queue>
static const int N = 100;
static const int INFTY = (1 << 21);
using namespace std;

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

	bfs(0);

    return 0;
}

C++: #include<iostream>
#include<string>
#include<algorithm>
#include<cstdio>
#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);
	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++) {
		printf("%d ", i + 1);
		if (d[i] == INFTY)
			printf("-1\n");
		else
			printf("%d\n", d[i]);
	}
}

int main(void) {
	int u, v, k;

	scanf("%d", &n);
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			M[i][j] = 0;
		}
	}

	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++: //http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_11_C&lang=ja
//幅優先探索
#include <bits/stdc++.h>
#if LOCAL
#include "dump.hpp"
#else
#define dump(...)
#endif
using namespace std;
using ll=long long;
#define FOR(i,a,b) for(ll i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
template<class T>bool chmax(T &a, const T &b) {if (a<b) { a=b; return 1; } return 0;}
template<class T>bool chmin(T &a, const T &b) {if (b<a) { a=b; return 1; } return 0;}

template< typename T >
struct edge {
	int src, to;
	T cost;
	edge(int _to, T _cost) : src(-1), to(_to), cost(_cost) {}
	edge(int _src, int _to, T _cost) : src(_src), to(_to), cost(_cost) {}
	edge &operator=(const int &x) {
		to = x;
		return *this;
	}
	operator int() const { return to; }
};

template< typename T>
struct node {
	vector<edge<T>> edges;
    ll dist=-1;
};

template< typename T >
using Edges = vector< edge< T > >;
template< typename T >
using WeightedGraph = vector< node< T > >;
using UnWeightedGraph = vector< vector< int > >;
template< typename T >
using Matrix = vector< vector< T > >;

int main() {
#if LOCAL&01
    std::ifstream in("./test/sample-1.in");
    //std::ifstream in("./input.txt");
    std::cin.rdbuf(in.rdbuf());
#else
    cin.tie(0);
    ios::sync_with_stdio(false);
#endif
    ll n; cin>>n;
    WeightedGraph<ll> graph(n+1);
    FOR(i,1,n+1){
        ll u,k; cin>>u>>k;
        REP(j,k){
            ll v; cin>>v;
            graph.at(u).edges.emplace_back(v,1);
        }
    }

    queue<ll> st;
    st.push(1);
    graph.at(1).dist=0;
    while(not st.empty()){
        auto cn = st.front();
        st.pop();
        auto& node = graph.at(cn);
        for(const auto& nn:node.edges){
            if(graph.at(nn).dist>=0) continue;
            graph.at(nn).dist = node.dist + 1;
            st.push(nn.to);
        }
    }

    FOR(i,1,n+1){
        cout<<i<<" "<<graph.at(i).dist<<endl;
    }
    return 0;
}

C++: #include<cstdio>
#include<queue>
using namespace std;
static const int INF=(1<<21);
static const int MAXN=101;
int main()
{
	int n,m[MAXN][MAXN],i,j,u,k,v,l,o,c=1,t[MAXN],z=2;
	queue<int> q;
	bool used[MAXN]={};
	scanf("%d",&n);
	for(i=1;i<n+1;i++){
		for(j=1;j<n+1;j++){
			m[i][j]=INF;
		}
	}
	for(i=0;i<n;i++){
		scanf("%d %d",&u,&k);
		for(j=0;j<k;j++){
			scanf("%d",&v);
			m[u][v]=1;
		}
	}
	q.push(1);
	used[1]=true;
	t[1]=0;
	while(1){
		l=q.front();
		q.pop();
		o=0;
		for(i=1;i<n+1;i++){
			if(m[l][i]==1&&used[i]==false){
				q.push(i);
				used[i]=true;
				t[i]=c;
				o=1;
			}
		}
		if(o==1){
			c++;
		}
		if(q.empty()){
			z=0;
			for(i=1;i<n+1;i++){
				if(used[i]==false){
					q.push(i);
					z=1;
					used[i]=true;
					break;
				}
			}
		}
		if(z==0){
			break;
		}
		if(z==1){
			c++;
			z=2;
		}
	}
	for(i=1;i<n+1;i++){
		printf("%d %d\n",i,t[i]);
	}
	return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<cstring>
#include<queue>
#define white 0
#define black -1
#define grey 1
using namespace std;
int a[110][110],n;
int d[110];
int color[110];

void bfs()
{
    memset(d,0,sizeof(d));
    queue<int> Q;
    d[1]=0;
    for(int i=1;i<=100;i++)
        color[i]=white;
    Q.push(1);
    while(!Q.empty())
    {
        int u=Q.front();
        Q.pop();
        for(int i=1;i<=n;i++)
        {
            if(a[u][i]==0)
                continue;
            if(d[i]!=0)
                continue;
                Q.push(i);
                color[i]=grey;
                d[i]=d[u]+1;
        }
    }
    for(int i=1;i<=n;i++)
   {
       printf("%d ",i);
       if(i==1) printf("%d",d[i]);
       else if(d[i]) printf("%d",d[i]);
       else printf("-1");
       printf("\n");
   }

}

int main()
{
   int key,d,x;
   memset(a,0,sizeof(a));
   scanf("%d",&n);
   for(int i=1;i<=n;i++)
   {
       scanf("%d%d",&key,&d);
       for(int j=1;j<=d;j++)
       {
        scanf("%d",&x);
        a[key][x]=1;
       }
   }
   bfs();
   return 0;
}