Go: package main

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

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
type Queue struct {
	arr []int
}

func (q *Queue) push(v int) {
	q.arr = append(q.arr, v)
}

func (q *Queue) pop() int {
	res := q.arr[0]
	q.arr = q.arr[1:]
	return res
}

func (q *Queue) isEmpty() bool {
	return len(q.arr) == 0
}

func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	G := make([][]int, N)
	for i := 0; i < N; i++ {
		u, k := sc.nextInt()-1, sc.nextInt()
		for j := 0; j < k; j++ {
			G[u] = append(G[u], sc.nextInt()-1)
		}
	}
	var q Queue
	seen := make([]int, N)
	for i := 0; i < N; i++ {
		seen[i] = -1
	}
	var search func(cur int)
	search = func(cur int) {
		for i := 0; i < len(G[cur]); i++ {
			next := G[cur][i]
			if seen[next] == -1 {
				q.push(next)
				seen[next] = seen[cur] + 1
			}
		}
	}
	q.push(0)
	seen[0] = 0
	for !q.isEmpty() {
		search(q.pop())
	}

	for i := 0; i < N; i++ {
		fmt.Fprintln(wtr, i+1, seen[i])
	}
	wtr.Flush()
}

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

using namespace std;

#define N 100
#define INF -1

int n,d[N],m[N][N];

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

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

C++: #include <iostream>
#include <algorithm>
#include <string>
#include <stack>
#include <cstdlib>
#include <queue>
#include <vector>
#include <set>

using namespace std;
int n,m,l,p;
bool a[100][100];
int D[100];
void  bfs ( int src) {
	queue<int> Q;
	Q.push(src);
	D[src]=0;
	while( ! Q.empty() ) {
		int cur = Q.front();
		Q.pop();
		for(int dst = 0; dst < n; dst++ ) {
			if( D[dst] == 0 && a[cur][dst] == 1 ) {
				D[dst] = D[cur] + 1;
				Q.push(dst);
			}
		}
	}
	for (int i = 0; i < n;i++) {
	cerr << i+1 <<  " " << D[i] <<  endl;
	}
}
int main() {
	cin >> n;
	for ( int i = 0;i < n;i++) {
		for(int j= 0; j < n;j++) {
			a[i][j] = 0;
		}
	}
	for (int i = 0;i < n; i++){
		cin >> m;
		cin >> l;
		for(int j = 0; j < l;j++) {
			cin >> p;
			a[m-1][p-1] = 1;
		}
	}
	bfs(0);
}

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

using namespace std;

int d[100];
vector<int> adj[100];

void bfs(int n, int start) {
	queue<int> que;

	for (int i = 0; i < n; i++)
		d[i] = i == start ? 0 : -1;

	que.push(start);
	while(!que.empty()) {
		int from = que.front();
		que.pop();

		for (int& to : adj[from])
			if (d[to] == -1) {
				d[to] = d[from] + 1;
				que.push(to);
			}
	}
}

int main() {
	int n;

	cin >> n;

	for (int i = 0; i < n; i++) {
		int u, k;
		cin >> u >> k;
		while (k--) {
			int v;
			cin >> v;
			adj[u - 1].push_back(v - 1);
		}
	}

	bfs(n, 0);

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

	return 0;
}

C++: #include <iostream>
#include <iomanip>
#include <vector>
#include <set>
#include <string>
#include <queue>
#include <algorithm>
#include <map>
#include <cmath>
#include <list>
#include <stack>
#include <cstdio>
#include <cstdlib>
#include <cstring>

#define rep(i, n) for (int i = 0; i < n; i++)

using namespace std;

const int INF = 1 << 30;
const int MOD = 1000000007;
const int MAX = 100000;
const int N = 100;

vector<int> G[N];
int d[N];

int main() {
	int n; cin >> n;
	rep(i, n) {
		int _, n2; cin >> _ >> n2;
		rep(j, n2) {
			int k; cin >> k; k--;
			G[i].push_back(k);
		}
	}
	rep(i, n) d[i] = -1;

	queue<int> Q;
	Q.push(0);
	d[0] = 0;
	while (!Q.empty()) {
		int i = Q.front(); Q.pop();
		for (auto j : G[i]) {
			if (d[j] != -1) continue;
			d[j] = d[i] + 1;
			Q.push(j);
		}
	}
	rep(i, n) cout << i+1 << ' ' << d[i] << endl;
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
// Welcome to my source code!

static const int N = 100;
static const int INFTY = (1<<21);

int n, M[N][N] = {};
int d[N];

void bfs(int s) {
    queue<int> q;
    q.push(s);
    for (int i = 0; i < n; i++) d[i] = INFTY;
    d[s] = 0;
    int u;
    while (!q.empty()) {
        u = q.front(); q.pop();
        for (int v = 0; v < n; v++) {
            if (M[u][v] == 0) continue;
            if (d[v] != INFTY) continue;
            d[v] = d[u] + 1;
            q.push(v);
        }
    }
    for (int i = 0; i < n; i++) {
        cout << i+1 << ' ' << ((d[i] == INFTY) ? (-1) : d[i]) << endl;
    }
}

int main() {
    int u, k, v;
    cin >> n;
    for (int i = 0; i < n; i++) {
        cin >> u >> k;
        u--;
        for (int j = 0; j < k; j++) {
            cin >> v;
            v--;
            M[u][v] = 1;
        }
    }
    bfs(0);
}