Go: package main

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

type vertexId int

type vertex struct {
	id vertexId
	visitedAt int
	adjs []vertexId
}

func createVertex(id int, adjsInt []int) vertex {
	adjs := make([]vertexId, len(adjsInt))
	for i := 0; i < len(adjs); i++ {
		adjs[i] = vertexId(adjsInt[i])
	}
	return vertex{
		id: vertexId(id),
		visitedAt: -1,
		adjs: adjs,
	}
}

func (v *vertex) isVisited() bool {
	return v.visitedAt >= 0
}

func bfs(id vertexId, vqueue []vertexId, vertices []vertex) {
	vertex := &vertices[id-1]
	for _, vid := range vertex.adjs {
		if !vertices[vid-1].isVisited() {
			(&vertices[vid-1]).visitedAt = vertex.visitedAt+1
			vqueue = append(vqueue, vid)
		}
	}
	if len(vqueue) > 0 {
		nextId := vqueue[0]
		nextVqueue := vqueue[1:]
		bfs(nextId, nextVqueue, vertices)
	}
}

func solveBfs(vertices []vertex) {
	vertex := &vertices[0]
	vertex.visitedAt = 0
	vqueue := make([]vertexId, 0)
	bfs(vertex.id, vqueue, vertices)
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	vertices := make([]vertex, n)
	for i := 0; i < n; i++ {
		id, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjN, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjs := make([]int, adjN)
		for j := 0; j < adjN; j++ {
			adjId, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			adjs[j] = adjId
		}
		vertices[i] = createVertex(id, adjs)
	}

	solveBfs(vertices)

	for i := 0; i < n; i++ {
		fmt.Printf("%d %d\n", vertices[i].id, vertices[i].visitedAt)
	}
}

func nextText(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

func nextInt(sc *bufio.Scanner) (int, error) {
	return strconv.Atoi(nextText(sc))
}

C++: #include <bits/stdc++.h>
#include<math.h>
#define rep(i,n) for (int i = 0; i < (n) ; ++i)
using namespace std;
using ll = long long ;
using P = pair<int , int> ;
#define PI 3.14159265358979323846264338327950
#define INF 1e18 

int main() {
    int n ;
    cin >> n ;
    vector<int> list [n] ;
    rep(i, n){
        int v, k;
        cin >> v >> k ;
        v-- ;
        rep(j, k){
            int g ;
            cin >> g  ;
            g-- ;
            list[v].push_back(g) ;
        }
    }
    queue<P> que ;
    vector<int> d (n, -1) ;
    que.push(P(0, 0)) ;
    while(!que.empty()) {
        P st = que.front() ;
        que.pop() ;
        if(d[st.first] > -1){
            continue ;
        }
        else {
            int f = st.first ;
            int e = st.second ;
            d[f] = e ;
            for(int u : list[f]){
                que.push(P(u, e + 1)) ;
            }
        }
 
    }
    rep(i, n){
        cout << i + 1 << " " << d[i] << endl ;
    }
}

C++: #include <iostream>
#include <iomanip>
#include <utility>
#include <cmath>
#include <random>
#include <vector>
#include <map>
#include <set>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <algorithm>
using namespace std;

#define rep(i,n) for(int i = 0; i<n; ++i)
#define REP(i,n) for(int i = 1; i<=n; ++i)
#define all(x) begin(x),end(x)
typedef long long ll;
typedef pair<int,int> ip;
typedef pair<ll,ll> lp;
const int inf = 1001001000;
const ll INF = 1LL<<60;
const int MOD = (int)1e9 + 7;

int main(){
	int n;
	cin>>n;
	vector<int> ans(110,-1);
	vector<vector<int>> input (110);
	REP(i,n){
		int el_siz;
		cin>>el_siz>>el_siz;
		vector<int> el(el_siz);
		rep(j,el_siz)cin>>el[j];
		input[i] = el;
	}
	queue<int> Q;
	int cnt = 0;
	ans[1] = 0;
	Q.push(1);
	while(!Q.empty()){
		int node = Q.front();
		Q.pop();
		rep(i,input[node].size()){
			if(ans[input[node][i]] == -1){
				ans[input[node][i]] = ans[node]+1;
				Q.push(input[node][i]);
			}
		}
	}
	REP(i,n)cout<<i<<' '<<ans[i]<<endl;
	return 0;
}

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

int n;

int V[100][100];
int D[100];
int d = 0;

std::queue<int> Q;

void bfs(int r) {
    Q.push(r);
    D[r] = 0;
    while (Q.size()) {
        r = Q.front();
        Q.pop();
        for (int i = 0; i < n; i++) {
            if ((D[i] == -1) && (V[r][i] == 1)) {
                Q.push(i);
                D[i] = D[r] + 1;
            }
        }
    }
}


int main() {
    std::cin >> n;
    for (int i = 0; i < n; i++) {
        int id, e_num;
        std::cin >> id >> e_num;
        for (int j = 0; j < e_num; j++) {
            int t;
            std::cin >> t;
            V[id - 1][t - 1] = 1;
        }
    }

    for (int i = 0; i < n; i++) {
        D[i] = -1;
    }

    bfs(0);
    for (int i = 0; i < n; i++) {
        std::cout << i + 1 << " " << D[i] << std::endl;
    }
}