Go: package main

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

var distance []int

type queue struct {
	q    []int
	head int
	tail int
}

func (q *queue) push(n int) {
	q.q[q.tail] = n
	q.tail++
}

func (q *queue) pop() int {
	q.head++
	return q.q[q.head-1]
}

func (q *queue) isEmpty() bool {
	return q.head == q.tail
}

func makeAdjList() [][]int {
	var n int
	fmt.Scanf("%d", &n)

	adj := make([][]int, n)
	for i := 0; i < n; i++ {
		adj[i] = make([]int, n)
	}

	sc := bufio.NewScanner(os.Stdin)
	for i := 0; i < n; i++ {
		sc.Scan()
		nodeInfo := strings.Split(sc.Text(), " ")
		outDegree, _ := strconv.Atoi(nodeInfo[1])

		if outDegree > 0 {
			for k := 0; k < outDegree; k++ {
				j, _ := strconv.Atoi(nodeInfo[k+2])
				j-- // convert 1 based to 0 based
				adj[i][j] = 1
			}
		}
	}

	return adj
}

func bfs(graph [][]int, s int) {
	distance = make([]int, len(graph))

	infty := -1
	for i := 0; i < len(distance); i++ {
		distance[i] = infty
	}
	distance[s] = 0

	q := &queue{make([]int, 1000), 0, 0}
	q.push(s)

	for !q.isEmpty() {
		u := q.pop()
		for i := 0; i < len(graph); i++ {
			if graph[u][i] == 0 {
				continue // u, i間に辺がない場合
			}
			if distance[i] != infty {
				continue // 訪問済みの場合
			}
			// 訪問するnodeの始点からの距離を設定し、訪問キューに入れる
			distance[i] = distance[u] + 1
			q.push(i)
		}
	}

	// print distance
	for i, d := range distance {
		fmt.Printf("%d %d\n", i+1, d)
	}
}

func main() {
	adj := makeAdjList()
	bfs(adj, 0)
}

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

struct BFS{
    vector<vector<int>> adj;
    queue<int> Q;
    vector<int> d;
    int n_;
    BFS(int n):adj(n),d(n,-1){
        n_ = n;
    }

    void init(){
        rep(i,n_){
            int u,k;cin>>u>>k;u--;
            rep(i,k){
                int tmp;cin>>tmp;tmp--;
                adj[u].push_back(tmp);
            }
        }
    }

    void visit(int u){
        Q.push(u);
        d[u] = 0;
        while(!Q.empty()){
            int v = Q.front();Q.pop();
            for(int h:adj[v]){
                if(d[h] == -1){
                    Q.push(h);
                    d[h] = d[v] + 1;
                }
            }
        }
    }
    void solve(){
        init();
        visit(0);
        rep(i,n_){
            cout<<i+1<<" "<<d[i]<<endl;
        }
    }

};

int main(){
    int n;cin>>n;
    BFS bfs(n);
    bfs.solve();
    return 0;
}

C++: #include <bits/stdc++.h>
#include <bits/stdc++.h>
#define r(i,a,n) for(int i=a;i<n;i++)
using namespace std;
int a[101][101],start[101],end[101],n,p=0,v[101];
queue<int> q;
void bfs(int u){
	q.push(u);
	v[u]++;
	while(!q.empty()){
		u=q.front();q.pop();
		r(i,1,n+1)if(!v[i]&&a[u][i]){
			v[i]++;
			q.push(i);
			start[i]=start[u]+1;
		}
	}
}
int main(){
	int q,qq,qqq;
	cin>>n;
	r(i,0,n){
		cin>>q>>qq;
		r(i,0,qq){
			cin>>qqq;
			a[q][qqq]++;
		}
	}
	r(i,1,n+1)if(!v[i])
	bfs(i);
	r(i,1,n+1)cout<<i<<' '<<start[i]<<endl;
}

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


using namespace std;


static const  int N =  100;
static const  int no =  -1;

int graph[N][N] = {{}};
int d[N] = {};
int n;

void bfs(int v){
  queue<int> Q; 
  Q.push(v);

  int u;
    for(int i = 1;i <= n; i++){
      d[i] = no;
    
}
  d[v] = 0;

  while(!Q.empty()){
    u = Q.front();
    Q.pop();

    for(int i = 1;i <= n; i++){
      if(graph[u][i] == 0) continue;
      if(d[i] != no) continue;
      d[i] = d[u] +1;
      Q.push(i);
    }
  }
}


int main(){
  int u,v,k;
  //graph
  cin >> n ;

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


  bfs(1);

  for(int i = 1;i <= n; i++){
    cout << i << ' ' << d[i] << endl;
  }

  return 0;
}

C++: #include<iostream>
#include<queue>
#include<vector>
using namespace std;
int main(){
  queue<int> q;
  int n,a,k,u,c[101];
  vector<int>  d[101];
  cin>>n;for(int i=0;i<n;i++){
    cin>>u>>k;c[i+1]=-1;
    d[u].resize(k);
    for(int j=0;j<k;j++) cin>>d[u][j];
  }q.push(1),c[1]=0;
  while(!q.empty()){
   a=q.front(),q.pop();
    for(int i=0;i<d[a].size();i++)
      if( d[a][i]>1 && c[d[a][i]]==-1) q.push(d[a][i]),c[d[a][i]]=c[a]+1;
  } for(int i=1;i<=n;i++) cout<<i<<" "<<c[i]<<endl;
  return 0;
}

C++: #include <array>
#include <vector>
#include <deque>
#include <queue>
#include <set>
#include <unordered_set>
#include <map>
#include <unordered_map>
#include <string>
#include <algorithm>
#include <numeric>
#include <functional>
#include <iterator>
#include <tuple>
#include <utility>
#include <limits>
#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <cstdint>
#include <cassert>

using namespace std;

#define FOR(i, start, end) for(int i = (start); i < (end); ++i)
#define REP(i, n) FOR(i, 0, n)

int n;
int mat[100][100];
int d[100];

void solve()
{
    fill(begin(d), end(d), -1);

    queue<int> q;
    q.push(0);
    d[0] = 0;

    while(!q.empty()) {
        int i = q.front(); q.pop();
        REP(j, n) {
            if(!mat[i][j]) continue;
            if(d[j] != -1) continue;

            d[j] = d[i] + 1;
            q.push(j);
        }
    }
}

int main()
{
    cin >> n;

    REP(i, n) {
        REP(j, n) {
            mat[i][j] = 0;
        }
    }

    REP(_, n) {
        int u, k;
        cin >> u >> k;

        REP(_, k) {
            int v;
            cin >> v;
            mat[u-1][v-1] = 1;
        }
    }

    solve();

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

    return 0;
}

C++: #include "bits/stdc++.h"

#define REP(i,num) for(ll i=0;i<(num);++i)
#define LOOP(i) while(i--)
#define ALL(c) c.begin(),c.end()
#define PRINTALL(c) for(auto pitr=c.begin();pitr!=c.end();++pitr){cout<<*pitr;if(next(pitr,1)!=c.end())cout<<' ';}cout<<endl;
#define PAIRCOMP(c,comp) [](const pair<ll,ll>& lhs,const pair<ll,ll>& rhs){return lhs.c comp rhs.c;}

using namespace std;
using ll = long long;

constexpr ll atcoder_mod = 1e9+7;

template<typename T=ll>
T in(){T x; cin >> x; return (x);}
template<typename T=ll,typename C=vector<T>>
C vecin(int N){C x(N);REP(i,N){x[i]=in<T>();}return move(x);}

void vout(){cout << endl;}
template<typename Head,typename... Tail>
void vout(Head&& h,Tail&&... t){cout << ' ' << h;vout(forward<Tail>(t)...);}
void out(){cout << endl;}
template<typename Head,typename... Tail>
void out(Head&& h,Tail&&... t){cout << h;vout(forward<Tail>(t)...);}

class ConnectNodeInfo{
	vector<vector<pair<ll,ll>>> graph;
public:
	ConnectNodeInfo(int node_num){
		graph.resize(node_num);
	}
	void AddNonDirectionalConnection(ll u,ll v,ll w){
		graph[u].emplace_back(v,w);
		graph[v].emplace_back(u,w);
	}
	void AddDirectionalConnection(ll u,ll v,ll w){
		graph[u].emplace_back(v,w);
	}
	vector<pair<ll,ll>>& operator[](ll index){
		return graph[index];
	}
	size_t size(){return graph.size();}
};

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout<<fixed<<setprecision(10);

	int N=in();
	ConnectNodeInfo connect(N);
	vector<int> V(N),D(N,-1);
	REP(i,N){
		V[i]=in()-1;
		int k=in();
		REP(j,k){
			int u=in()-1;
			connect.AddDirectionalConnection(V[i],u,1);
		}
	}
	queue<int> Q;
	Q.push(0);
	D[0]=0;
	while(!Q.empty()){
		auto X=Q.front();
		Q.pop();
		for(auto& x:connect[X]){
			if(D[x.first]==-1){
				D[x.first] = D[X]+1;
				Q.push(x.first);
			}
		}
	}
	REP(i,N) out(V[i]+1,D[i]);
	return 0;
}