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<bits/stdc++.h>

struct node{
    int d, flag;
    node(){
        d = 0;
        flag = 0;
    }
};

int main(void){
    int n;
    int ind, num, a;
    int time, ndi;

    std::cin >> n;
    std::vector<node> nd(n);
    std::vector<std::vector<int>> b(n, std::vector<int>(n));
    std::queue<int> st;

    for(int i = 0; i < n; i++){
        std::cin >> ind >> num;
        ind--;
        for(int i = 0; i < num; i++){
            std::cin >> a;
            a--;
            b[ind][a] = 1;
        }
    }

    time = 0;
    int x = 0;
    //for(int x = 0; x < n; x++){
        if(nd[x].flag == 0){
            ndi = x;
            time++;
            nd[x].flag = 1;
        
            st.push(x);
        }
    
        

        while(st.empty() != 1){
            //std::cout << ndi+1 << " " << time << std::endl;
            //time++;
            int tmp = -1;
            int tmp2;
            for(int i = 0; i < n; i++){
                if(b[ndi][i] == 1 && nd[i].flag == 0){
                    tmp = i;
                    tmp2 = x;
                    break;
                }
            }
            if(tmp == -1){
                //std::cout << ndi+1 << " " << time << std::endl;

                nd[ndi].flag = 1;
                st.pop();
                if(st.empty() != 1){
                    ndi = st.front();
                }

                continue;
            }

            nd[tmp].flag = 1;
            nd[tmp].d = nd[ndi].d + 1;
            st.push(tmp);
            
        }
    //}
    for(int i = 0; i < n; i++){
        if(nd[i].flag == 0 && i != 0){
            nd[i].d = -1;
        }
    }
    for(int i = 0; i < n; i++){
        std::cout << i+1 << " " << nd[i].d << std::endl;
    }

    return 0;
}

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

using namespace std;

int color[100];
int d[100];
int f[100];
int G[100][100];
int nt[100];
int n;

int WHITE = 1;
int GRAY = 2;
int BLACK = 3;

int _time = 0;

int next(int u) {
  for (int v = nt[u]; v < n; v++) {
    nt[u] = v + 1;
    if (G[u][v]) return v;
  }

  return -1;
}

void dfs(int r) {
  for (int i = 0; i < n; i++) nt[i] = 0;

  queue<int> S;

  S.push(r);
  color[r] = GRAY;

  while(!S.empty()){
    int u = S.front();

    while(1) {
      int v = next(u);

      if(v != -1) {
        if(color[v] == WHITE) {
          color[v] = GRAY;

          S.push(v);

          d[v] = d[u] + 1;
        }
      } else {
        break;
      }
    }

    S.pop();
  }
}

void dfs_init() {
  for(int i = 0; i < n; i++) {
    color[i] = WHITE;
  }

  dfs(0);

  for(int i = 0; i < n; i++) {
    if(color[i] == WHITE) {
      d[i] = -1;
    }
  }
}

int main() {
  int m, k, l;
  cin >> n;

  for (int i = 0; i < n; i++) {
    cin >> k;
    cin >> m;

    for (int j = 0; j < m; j++) {
      int l;
      cin >> l;

      G[k-1][l-1] = 1;
    }
  }

  for (int i = 0; i < n; i++) {
    dfs_init();
  }

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

C++: #include<bits/stdc++.h>
#define INF 0x3f3f3f3f
#define rep(i,n)for(int i=0;i<n;i++)
using namespace std;
typedef pair<int,int>P;

vector<int>E[100];
int d[100];
int main(){
	int n;cin>>n;
	rep(i,n){
		int u,k;cin>>u>>k;u--;
		rep(i,k){
			int v;cin>>v;v--;
			E[u].push_back(v);
		}
	}
	memset(d,0x3f,sizeof(d));
	queue<P>que;
	d[0]=0;que.push(P(0,0));
	while(!que.empty()){
		P p=que.front();que.pop();
		for(int u:E[p.second]){
			if(d[u]>p.first+1){
				d[u]=p.first+1;
				que.push(P(d[u],u));
			}
		}
	}
	rep(i,n){
		if(d[i]==INF)cout<<i+1<<" -1"<<endl;
		else cout<<i+1<<' '<<d[i]<<endl;
	}
}