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 <iostream>
#include <algorithm>
#include <vector>
#include <map>
#include <stack>
#include <queue>
#include <cmath>
#include <string>
using namespace std;
typedef vector<int> vint;
typedef vector<long long> vll;
typedef pair<int,int> pint;
typedef long long ll;
#define range(i,a,b) for(int i=a;i<b;++i)
#define rep(i,n) range(i,0,n)
#define INF 10000000000 //10^10
#define PI 3.141592
#define pb push_back

int main(){
    //内部処理は0indexで行う

    //入力
    int n;
    cin >> n;
    vector<vint> adj(n);
    rep(i,n){
        int u,k;
        cin >> u >> k;
        rep(j,k){
            int v;
            cin >> v;
            adj[u-1].pb(v-1);
        }
    }

    //計算
    vint d(n,-1);
    d[0]=0;
    queue<int> Q;
    Q.push(0);
    while(!Q.empty()){
        int cur=Q.front(); Q.pop();
        rep(i,adj[cur].size()){
            int dst=adj[cur][i];
            if(d[dst]==-1){
                d[dst]=d[cur]+1;
                Q.push(dst);
            }
        }
    }

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

C++: #define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
#define rep(i, n) for(ll i = 0; i < (n); ++i)
#define FOR(i, m, n) for(ll i = m; i < (n); i++)
#define all(x) (x).begin(),(x).end()
using namespace std;
typedef long long ll;
using vi = vector<int>;
using vii = vector<vi>;
using pii = pair<int, int>; 
using vl = vector<ll>;
using vll = vector<vl>;
using pll = pair<ll, ll>;

int main() {
    ll n;
    cin >> n;
    vll G(n);
    rep(i, n){
        ll u, k;
        cin >> u >> k;
        u--;
        rep(j, k){
            ll a;
            cin >> a;
            a--;
            if(a < 0) continue;
            G[u].push_back(a);
        }
    }
    
    vl dist(n, -1);
    queue<ll> que;
    dist[0] = 0;
    que.push(0);
    while(!que.empty()){
        ll v = que.front();
        que.pop();

        for(auto nv : G[v]){
            if(dist[nv] != -1) continue;
            dist[nv] = dist[v] + 1;
            que.push(nv);
        }
    }

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

C++: #include <stdio.h>
#include <queue>
#include <algorithm>

#define N 100
#define WHITE 0
#define GRAY 1
#define BLACK 2

using namespace std;

int n;
int M[N][N]; // ??£??\??????
int d[N]; // ???????????¢


void bfs()
{
    int i;
    for (i = 0; i < n; i++) {
        d[i] = -1;
    }
    
    int u;
    u = 0;
    d[u] = 0;
    queue<int> q;
    q.push(u);
    
    while (!q.empty()) {
        u = q.front();
        q.pop();
        for (i = 0; i < n; i++) {
            if (M[u][i] == 0) continue;
            if (d[i] != -1) continue;
            q.push(i);
            d[i] = d[u] + 1;
        }
    }
    
    for (i = 0; i < n; i++) {
        printf("%d %d\n", i+1, d[i]);
    }
}


int main()
{
    scanf("%d", &n);
    int i, j;
    for (i = 0; i < n; i++) {
        for (j = 0; j < n; j++) {
            M[i][j] = 0;
        }
    }
    
    // input graph
    int u, k, v;
    for (i = 0; i < n; i++) {
        scanf("%d %d", &u, &k);
        for (j = 0; j < k; j++) {
            scanf("%d", &v);
            M[u-1][v-1] = 1;
        }
    }
    
    bfs();
    
    return 0;
}

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

vector<vector<int>> g;
vector<int> d;

int main()
{
	int n;
	cin >> n;
	g = vector<vector<int>>( n );
	d = vector<int>( n );
	for( int i = 0; i < n; i++ ) {
		int u, k;
		cin >> u >> k;
		u--;
		for( int j = 0; j < k; j++ ) {
			int v;
			cin >> v;
			v--;
			g[u].push_back( v );
		}
	}

	queue<pair<int, int>> que;
	que.push( make_pair( 0, 1 ) );
	while( !que.empty() ) {
		int v, l;
		tie( v, l ) = que.front();
		que.pop();
		if( d[v] == 0 ) d[v] = l;
		for( int u : g[v] ) {
			if( d[u] ) continue;
			que.push( make_pair( u,  l + 1 ) );
		}
	}

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

C++: // #define _GLIBCXX_DEBUG
#include <bits/stdc++.h>

#define FOR(i, a, b) for (int i = (a); i < int(b); ++i)
#define RFOR(i, a, b) for (int i = (b)-1; i >= int(a); --i)
#define REP(i, n) FOR(i, 0, n)
#define REP1(i, n) FOR(i, 1, int(n) + 1)
#define RREP(i, n) RFOR(i, 0, n)
#define RREP1(i, n) RFOR(i, 1, int(n) + 1)
#define ALL(c) begin(c), end(c)

int _ = (
#ifndef LOCAL
    std::cin.tie(nullptr), std::ios::sync_with_stdio(false),
#endif
    std::cout.precision(10), std::cout.setf(std::ios::fixed));

using ll = long long;
using ld = long double;
template <typename T> using vec = std::vector<T>;
using pii = std::pair<int, int>;
using namespace std;

using graph = vec<vec<int>>;

constexpr int INF = numeric_limits<int>::max() / 3;
int n;
graph adj;

void bfs() {
  vec<int> d(n, INF);
  queue<int> q;
  d[0] = 0;
  q.emplace(0);

  while (!q.empty()) {
    const auto u = q.front();
    q.pop();
    for (auto&& v: adj[u]) {
      if (d[v] == INF) {
        d[v] = d[u] + 1;
        q.emplace(v);
      }
    }
  }
  REP(i, n) {
    cout << (i + 1) << " ";
    cout << (d[i] == INF ? -1 : d[i]) << endl;
  }
}

int main() {
  int u, v, k;
  cin >> n;
  adj.resize(n);
  REP(i, n) {
    cin >> u >> k;
    adj[i].resize(k);
    REP(j, k) {
      cin >> v;
      adj[i].emplace_back(v - 1);
    }
  }
  bfs();
  return 0;
}

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

#define NODE_NUM 100

queue<int> que;

class Node
{
private:
	int next_num;
	int next_node_list[NODE_NUM];
public:
	Node();
	void AddNextNode(int id);
	bool Search(int id);
	int dist;
	int check[NODE_NUM + 1];
};

Node::Node()
{
	next_num = 0;
	dist = -1;
	for (int i = 1; i <= NODE_NUM; i++) {
		check[i] = 0;
	}
}

void Node::AddNextNode(int id)
{
	next_node_list[next_num] = id;
	next_num++;
}

Node Node_list[NODE_NUM + 1];

bool Node::Search(int id)
{
	for (int k = 0; k < next_num; k++) {
		if (Node_list[next_node_list[k]].dist == -1) {
			Node_list[next_node_list[k]].dist = dist + 1;
		}
	}

	for (int i = 0; i < next_num; i++) {
		if (next_node_list[i] == id) return true;
	}
	
	for (int j = 0; j < next_num; j++) {
		if (Node_list[next_node_list[j]].check[id] == 0) {
			Node_list[next_node_list[j]].check[id] = 1;
			que.push(next_node_list[j]);
		}
	}
	
	return false;
}

int main(void)
{
	//input
	int n;
	cin >> n;
	for (int i = 0; i < n; i++) {
		int u, k;
		cin >> u;
		cin >> k;
		Node_list[u] = Node();
		for (int j = 0; j < k; j++) {
			int v;
			cin >> v;
			Node_list[u].AddNextNode(v);
		}
	}
	
	//dist
	Node_list[1].dist = 0;
	for (int i = 2; i <= n; i++) {
		bool ret = Node_list[1].Search(i);
		while (!ret && !que.empty()) {
			ret = Node_list[que.front()].Search(i);
			que.pop();
		};
		while (!que.empty()) {
			que.pop();
		}
	}

	//output
	for (int i = 1; i <= n; i++) {
		cout << i << " " << Node_list[i].dist << "\n";
	}
	
	return 0;
}