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<stdio.h>
#include<stack>
#include<iostream>
#include<string>
using namespace std;

int n = 0;
int u = 0;
int k[101];
int v[101][101];
int Short[101] = { 0 };
//into n = 0;
int p = 0;
int fptr = 0;
int lptr = 0;
int x1[10000];
int y1[10000];
void Enqueue(int y, int x)
{
	x1[lptr] = x;
	y1[lptr] = y;
	lptr = (lptr + 1) % n;
}
void bfs(int l) {
	int i;
	while (fptr!=lptr) {
		l=x1[fptr];
		p=y1[fptr];
		fptr = (fptr + 1) % n;
		if(Short[l]!=-1){
			continue;
		}
		for(i=0;i<k[l];i++){
			if(v[l][i]){
				Enqueue(p+1,v[l][i]);
			}
		}
		//Enqueue(v[l][in]);
		Short[l]=++p;
	}
}
int main()
{
	int i;
	int j;
	cin >> n;
	for (i = 0; i < n; i++) {
		cin >> u;
		cin >> k[u];
		for (j = 0; j < k[u]; j++) {
			cin >> v[u][j];
		}
	}
	Enqueue(-1,1);
	for(i=0;i<n+1;i++){
		Short[i]=-1;
	}
	bfs(0);
	cout << "\n";
	
	for (i = 1; i < n + 1; i++) {
		cout << i << " " << Short[i] << endl;
	}
}

C++: #include<iostream>
#include<queue>
#include <limits>
using namespace std;
#define N 100

int inf = numeric_limits<int>::max();
int n, M[N][N], d[N];

void bfs(int s) {
    queue<int> q;
    q.push(s);
    for (int i; i<n; i++) {
        d[i] = inf;
    }
    d[s] = 0;
    int u;
    while (!q.empty()) {
        u = q.front(); // Get the first element
        q.pop();
        for (int v=0; v<n; v++) {
            if (M[u][v]==0) {
                continue;  
            }
            if (d[v]!=inf) {
                // Already visited
                continue;
            }
            d[v] = d[u] +1;
            q.push(v);
        }
    }
    for (int i=0; i<n; i++) {
        if (d[i]!=inf) {
            cout << i+1 << " " << d[i] << endl;
        } else {
            cout << i+1 << " " << -1 << endl;
        }
    }
}

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

    bfs(0);
    return 0;
}

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

#define INFTY (1 << 30)

void BFS(bool mT[][100], int firstVerVal, int verNum, int distance[]) {
	queue<int>  verQ;
	verQ.push(firstVerVal);
	for (int i = 0; i < verNum; i++)
		distance[i] = INFTY;
	distance[firstVerVal] = 0;

	while (!verQ.empty()) {
		int curVerVal = verQ.front();
		verQ.pop();
		for (int i = 0; i < verNum; i++) {
			if (!mT[curVerVal][i] || distance[i] != INFTY) continue;
			distance[i] = distance[curVerVal] + 1;
			verQ.push(i);
		}
	}
}

int main() {
	bool matrixTable[100][100];
	int distance[100];
	int verNum;
	cin >> verNum;

	for (int i = 0; i < verNum; i++)
		for (int j = 0; j < verNum; j++)
			matrixTable[i][j] = false;
		
	for (int i = 0; i < verNum; i++) {
		int anyVerVal, anyVerNum;
		cin >> anyVerVal >> anyVerNum;
		for (int j = 0; j < anyVerNum; j++) {
			int verValue; cin >> verValue;
			matrixTable[anyVerVal - 1][verValue - 1] = true;
		}
	}

	BFS(matrixTable, 0, verNum, distance);

	for (int i = 0; i < verNum; i++) {
		cout << i + 1 << " " << distance[i] << endl;
	}

	return 0;
}

C++: #include<iostream>
#include<queue>
using namespace std;
int m[105][105],n,v[105],d[105];
void bfs(int s)
{
    v[s]=true;
    d[s]=0;
    queue<int>q;
    q.push(s);
    while(!q.empty())
    {
        int u=q.front();q.pop();
        for(int i=0;i<n;i++)
        {
             if(m[u][i]&&!v[i])
            {
                d[i]=d[u]+1;
                v[i]=true;
                q.push(i);
            }
        }
    }
}
int main()
{
    cin>>n;
    for(int i=0;i<n;i++)d[i]=-1;
    for(int i=0;i<n;i++)
    {
        int u,v,k;
        cin>>u>>k;
        for(int j=0;j<k;j++)
        {
            cin>>v;
            m[u-1][v-1]=true;
        }
    }
    bfs(0);
    for(int i=0;i<n;i++)cout<<i+1<<' '<<d[i]<<endl;
    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MOD=1000000007;
#define INF 1LL<<30
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define all(x) (x).begin(),(x).end()

vector<vector<int>> G;

// O(HW)
int n;
int d[110];
void bfs(){
    queue<int> que;
    
    que.push(0); // (0,0)スタート
    d[0]=0;
    while(!que.empty()){
        int p=que.front();
        que.pop();
        for(int nv : G[p]){
            if(d[nv]!=-1) continue;
            que.push(nv);
            d[nv]=d[p]+1;
        }
    }
}

int main() {
    
    cin>>n;
    G.resize(n);
    rep(i,n){
        int u,k;
        cin>>u>>k;
        u--;
        rep(j,k){
            int v;
            cin>>v;
            v--;
            G[u].push_back(v);
        }
    }

    rep(i,n) d[i]=-1;
    bfs();

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

}

C++: #include<bits/stdc++.h>
using namespace std;
int i,j,n,u,k,v,g[101][101],d[101],f[101];
int main(void){
  for(i=1;i<101;i++)d[i]=1<<30;
  d[1]=0;
  cin>>n;
  for(i=0;i<n;i++){
    cin>>u>>k;
    for(j=0;j<k;j++){
      cin>>v;
      g[u][v]++;
    }
  }
  queue<int>q;
  q.push(1);
  while(!q.empty()){
    u=q.front();q.pop();
    f[u]=1;
    for(i=1;i<101;i++){
      if(g[u][i]&&!f[i]){
        d[i]=min(d[i],d[u]+1);
        q.push(i);
      }
    }
  }
  for(i=1;i<=n;i++)cout<<i<<" "<<(d[i]==1<<30?-1:d[i])<<endl;
  return 0;
}