Go: package main

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

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

type Graph struct {
	M [N][N]int
	d [N]int
}

func (g *Graph) bfs(s, n int) string {
	var q []int
	q = append(q, s) // push

	for i := 0; i < n; i++ {
		g.d[i] = INFTY
	}
	g.d[s] = 0

	for len(q) != 0 {
		u := q[0]
		q = q[1:] // pop
		for v := 0; v < n; v++ {
			if g.M[u][v] == 0 || g.d[v] != INFTY {
				continue
			}
			g.d[v] = g.d[u] + 1
			q = append(q, v) // push
		}
	}

	var out bytes.Buffer
	for i := 0; i < n; i++ {
		if g.d[i] == INFTY {
			out.WriteString(fmt.Sprintf("%d -1\n", i+1))
			continue
		}
		out.WriteString(fmt.Sprintf("%d %d\n", i+1, g.d[i]))
	}

	return strings.TrimRight(out.String(), "\n")
}

func answer(reader io.Reader) string {
	sc := bufio.NewScanner(reader)
	sc.Split(bufio.ScanWords)

	sc.Scan()
	n, _ := strconv.Atoi(sc.Text())

	var g Graph
	for i := 0; i < n; i++ {
		sc.Scan()
		u, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		k, _ := strconv.Atoi(sc.Text())
		u--
		for j := 0; j < k; j++ {
			sc.Scan()
			v, _ := strconv.Atoi(sc.Text())
			v--
			g.M[u][v] = 1
		}
	}

	return g.bfs(0, n)
}

func main() {
	fmt.Println(answer(os.Stdin))
}

C++: #include <iostream>
#include <vector>
#include <queue>
using namespace std;
static const int MAX=101;

vector<int> Adjacency[MAX];
int dt[MAX];
bool Visited[MAX];

void bfs(int i)
{
    queue<int> Q;
    dt[i]=0;Q.push(i);
    Visited[i]=true;
    int d=0;
    while(!Q.empty())
    {
        int p=Q.front();Q.pop();d=dt[p]+1; //important
        for(int j=0;j<Adjacency[p].size();j++)
        {
            if(Visited[Adjacency[p][j]]==true) continue;
            //else
            Q.push(Adjacency[p][j]); Visited[Adjacency[p][j]]=true;
            dt[Adjacency[p][j]]=d;
        }
    }
}
int main()
{
    int n;
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        int j,num;
        cin>>j>>num;
        for(int k=0;k<num;k++)
        {
            int t;cin>>t;
            Adjacency[j].push_back(t);
        }
    }
    bfs(1);
    for(int i=1;i<=n;i++)
    {
        cout<<i<<' '<<dt[i]<<endl;
    }
}

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

typedef unsigned long long ull;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<double, double> pdd;
typedef vector<vector<ll>> Graph;

const ll mod = 1e9 + 7;
//const ll mod = 998244353;

#define REP(i,n) for(ll i=0;i<(ll)n;i++)
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define spa << " " <<
#define fi first
#define se second

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 (a>b) { a=b; return 1; } return 0; }

template<class S, class T> ostream& operator << (ostream& os, const pair<S, T> v){
os << "(" << v.first << ", " << v.second << ")"; return os;
}
template<class T> ostream& operator << (ostream& os, const vector<T> v){
for(int i = 0; i < (int)v.size(); i++){if(i > 0){os << " ";} os << v[i];} return os;
}
template<class T> ostream& operator << (ostream& os, const vector<vector<T>> v){
for(int i = 0; i < (int)v.size(); i++){if(i > 0){os << endl;} os << v[i];} return os;
}

template<typename T> void debug(vector<vector<T>>&v,ll h,ll w){for(ll i=0;i<h;i++)
{cerr<<v[i][0];for(ll j=1;j<w;j++)cerr spa v[i][j];cerr<<endl;}};
template<typename T> void debug(vector<T>&v,ll n){if(n!=0)cerr<<v[0];
for(ll i=1;i<n;i++)cerr spa v[i];
cerr<<endl;};

string num2bit(ll num, ll len){
    string bit = "";
    REP(i, len){
    bit += char('0'+(num>>i & 1));
    }
    return bit;
}

vector<int> graph_bfs(Graph &G, vector<ll> &s){
    const int N = G.size();
    vector<int> dist(N, -1);
    queue<int> qu;

    // initialization
    for(auto v: s){
        qu.push(v);
        dist[v] = 0;
    }

    while(!qu.empty()){
        int now = qu.front();qu.pop();
        for(auto next: G[now]){
            if(dist[next] != -1) continue;
            dist[next] = dist[now] + 1;
            qu.push(next);
        }
    }

    return dist;
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    ll n;
    cin >> n;
    Graph G(n);
    REP(i, n){
        ll u, k;
        cin >> u >> k;
        u--;
        REP(j, k){
            ll v;
            cin >> v;
            v--;
            G[u].push_back(v);
        }
    }

    vector<ll> s = {0};

    auto dist = graph_bfs(G, s);

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

    return 0;
}

C++: #include <iostream>
#include <vector>
#include <queue>
#include <string>
#include <algorithm>
#include <utility>

using namespace std;

#define REP(var, count) for(int var=0; var<count; var++)

int main(void) {
	int N;
	cin >> N;
	
	vector<int> rin[105];
	int ans[105];
	
	REP(i, N) {
		int u, k;
		cin >> u >> k;
		
		REP(j, k) {
			int c;
			cin >> c;
			
			rin[u].push_back(c);
		}
		
		ans[i] = -1;
	}
	ans[N] = -1;
	
	ans[1] = 0;
	queue<int> que;
	que.push(1);
	
	while(que.size()) {
		int s = que.front();
		que.pop();
		
		//cerr << "checking " << s << endl;
		
		REP(j, rin[s].size() ) {
			//cerr << "edge to " << rin[s][j] << endl;
			if ( ans[rin[s][j]] == -1 ) {
				ans[rin[s][j]] = ans[s] + 1;
				que.push(rin[s][j]);
			}
		}
	}
	
	for(int i=1; i<=N; i++) {
		cout << i << " " << ans[i] << endl;
	}
}