Go: package main

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

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)
	nodes := make([]Node, n)

	for i := 0; i < n; i++ {
		nodes[i].list = make([]int, 0)
		nodes[i].d = -1
	}

	for i := 0; i < n; i++ {
		u := getNextInt(scanner)
		k := getNextInt(scanner)
		u--
		for ii := 0; ii < k; ii++ {
			v := getNextInt(scanner)
			v--
			nodes[u].list = append(nodes[u].list, v)
		}
	}

	queue := make([]int, n)
	queue[0] = 0
	nodes[0].d = 0
	d := 0
	i, j := 0, 1
	for i < j {
		d++
		prev := j
		for i < prev {
			for k, l := 0, len(nodes[queue[i]].list); k < l && i < n; k++ {
				if nodes[nodes[queue[i]].list[k]].d != -1 {
					continue
				}
				nodes[nodes[queue[i]].list[k]].d = d
				queue[j] = nodes[queue[i]].list[k]
				j++
			}
			i++
		}
	}

	for i := 0; i < n; i++ {
		fmt.Fprintln(writer, fmt.Sprintf("%d %d", i+1, nodes[i].d))
	}

	writer.Flush()
}

// Node ...
type Node struct {
	list []int
	d    int
}

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;
    }
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, ll> P;
typedef pair<ll, P> P3;
typedef pair<P, P> PP;
constexpr ll MOD = ll(1e9 + 7);
constexpr int IINF = INT_MAX;
constexpr ll LLINF = LLONG_MAX;
constexpr int MAX_N = int(1e5) + 5;
constexpr double EPS = 1e-9;
constexpr int di[] = {0, 1, 0, -1}, dj[] = {1, 0, -1, 0};
#define REP(i, n) for (int i = 0; i < n; i++)
#define REPR(i, n) for (int i = n; i > 0; i--)
#define SORT(v) sort((v).begin(), (v).end())
#define SORTR(v) sort((v).rbegin(), (v).rend())
#define ALL(v) (v).begin(), (v).end()

int main() {
    vector<vector<int> > g;
    int n;
    cin >> n;
    g.resize(n);
    for(int i=0;i<n;i++){
        int v, k;
        cin >> v >> k;
        v--;
        for(int j=0;j<k;j++){
            int u;
            cin >> u;
            u--;
            g[v].push_back(u);
        }
    }
    vector<int> d(n, IINF);
    queue<int> que;
    que.push(0);
    d[0] = 0;
    que.push(0);
    while(!que.empty()){
        int v = que.front();
        que.pop();
        for(auto u : g[v]){
            if(d[u] == IINF){
                d[u] = d[v]+1;
                que.push(u);
            }
        }
    }
    for(int i=0;i<n;i++){
        cout << i+1 << " " << (d[i] < IINF ? d[i] : -1) << endl;
    }
    return 0;
}

C++: # include <bits/stdc++.h>
# define pb push_back
# define int long long
using namespace std;
void _cin(){} template <class Head, class... Tail> void _cin(Head&& head, Tail&&... tail){ cin >> head; _cin(forward<Tail>(tail)...); }
#define Cin(Type, ...) Type __VA_ARGS__; _cin(__VA_ARGS__)
#define Cinv(Type, xs, n) vector<Type> xs(n); rep(i, n) cin >> xs[i]
#define Cinv2(Type, xs, ys, n) vector<Type> xs(n), ys(n); rep(i, n) cin >> xs[i] >> ys[i]
#define Cinv3(Type, xs, ys, zs, n) vector<Type> xs(n), ys(n), zs(n); rep(i, n) cin >> xs[i] >> ys[i] >> zs[i]
#define Cinvv(Type, xs, h, w) vector<vector<Type>> xs(h, vector<int>(w)); rep(i, h) rep(j, w) cin >> xs[i][j]
void Print() { cout << endl; }
template <class Head, class... Tail> void Print(Head&& head, Tail&&... tail) { cout << head; if (sizeof...(tail) != 0) cout << " "; Print(forward<Tail>(tail)...); }
template <class Type> void Print(vector<Type> &vec) { for (auto& a : vec) { cout << a; if (&a != &vec.back()) cout << " "; } cout << endl; }
template <class Type> void Print(vector<vector<Type>> &df) { for (auto& vec : df) { Print(vec); } }
void Debug() { cerr << endl; }
template <class Head, class... Tail> void Debug(Head&& head, Tail&&... tail) { cerr << head; if (sizeof...(tail) != 0) cerr << " "; Debug(forward<Tail>(tail)...); }
template <class Type> void Debug(vector<Type> &vec) { for (auto& a : vec) { cerr << a; if (&a != &vec.back()) cerr << " "; } cerr << endl; }
template <class Type> void Debug(vector<vector<Type>> &df) { for (auto& vec : df) { Debug(vec); } }
vector<int> range(int n) {
    vector<int> ar(max((int)0, n));
    iota(ar.begin(), ar.end(), 0);
    return ar;
}

signed main() {
    Cin(int, n); // 頂点数
    vector<vector<int>> G(n);
    for (auto i : range(n)) {
        Cin(int, u, k);
        u--;
        for (auto j : range(k)) {
            Cin(int, v);
            v--;
            G[u].pb(v);
        }
    }

    vector<int> dist(n, -1);
    queue<int> que;
    que.push(0);
    dist[0] = 0;
    while (!que.empty()) {
        int now = que.front(); que.pop();
        for (auto nxt : G[now]) {
            if (dist[nxt] != -1) continue;
            dist[nxt] = dist[now] + 1;
            que.push(nxt);
        }
    }

    for (auto i : range(n)) {
        cout << i+1 << " " << dist[i] << "\n";
    }

    return 0;
}