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 <iostream>
#include <queue>
#include <vector>


class Graph {
  public:
    Graph(int n) : n(n) {
        adj_arr = std::vector<std::vector<int>>(n);
        depth = std::vector<int>(n, -1);
    }

    void breadth_search(int i, int d) {
        std::queue<int> queue;
        depth[i] = d;
        
        for (auto && v : adj_arr[i]) {
            if (depth[v - 1] == -1 || depth[v - 1] > d) {
                queue.push(v - 1);
            }
        }

        while (!queue.empty()) {
            int v = queue.front();
            queue.pop();
            breadth_search(v, d + 1);
        }
    }

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

  public:
    std::vector<std::vector<int>> adj_arr;
    std::vector<int> depth;
    
  private:
    int n;
};


int main () {
    int n;
    std::cin >> n;

    Graph graph(n);

    for (int i = 0; i < n; i++) {
        int u, k;
        std::cin >> u >> k;
        std::vector<int> arr(k);
        
        for (int j = 0; j < k; j++) {
            std::cin >> arr[j];
        }
        graph.adj_arr[u - 1] = arr;
    }

    graph.breadth_search(0, 0);
    graph.print();
}

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

vector<vector<int>> v;
vector<int> d, t;

void bfs(){
  int time = 0;
  queue<int> q;
  q.push(0);

  while(!q.empty()){
    int node = q.front();
    q.pop();

    for(int i=0; i<v.size(); ++i){
      if(v[node][i] == 1 && t[i] == -1){
         q.push(i);
         t[i] = t[node] + 1;
       }
    }
  }
}

int main(){
  int n; cin >> n;

  v.resize(n);
  d.resize(n);
  t.resize(n);
  for(int i=1; i<n; ++i) t[i] = -1;

  for(int i=0; i<n; ++i) v[i].resize(n);

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

  bfs();

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

C++: #include <iostream>
#include <fstream>
#include <stdio.h>
#include <math.h>
#include <algorithm>
#include <queue>

using namespace std;

int n;
int arr[100][100];
int time_saver[100][2];
int now_time;
queue< pair < int, int > > q;

void search(int fi, int fnow_time){
    time_saver[fi][0] = fnow_time;
    for(int i=0; i<100; i++){
        if(arr[fi][i] && !time_saver[arr[fi][i]-1][0]){
            int a = fnow_time+1;
            q.push(make_pair(arr[fi][i]-1, a));
        }
    }
}

int main(int argc, const char * argv[]) {
    
    /////////
    //write//
    /////////
    
    cin >> n;
    now_time = 0;
    for(int i=0; i<100; i++){
        for(int j=0; j<100; j++){
            arr[i][j] = 0;
        }
        for(int j=0; j<2; j++){
            time_saver[i][j] = 0;
        }
    }
    
    for(int i=0; i<n; i++){
        int node, degree; cin >> node >> degree;
        for(int j=0; j<degree; j++){
            int tmp; cin >> tmp;
            arr[node-1][tmp-1] = tmp;
        }
    }
    
    for(int i=0; i<1; i++){
        if(time_saver[i][0])continue;
        search(i, now_time);
        while(!q.empty()){
            int tmp = q.front().first;
            int tmp2 = q.front().second;
            now_time = max(now_time, q.front().second+1);
            q.pop();
            if(time_saver[tmp][0] || tmp == 0)continue;
            search(tmp, tmp2);
        }
    }
    for(int i=1; i<n; i++){
        if(!time_saver[i][0])time_saver[i][0] = -1;
    }
    
    for(int i=0; i<n; i++){
        for(int j=0; j<1; j++){
            if(j)cout << " ";
            else cout << i+1 << " ";
            cout << time_saver[i][j];
        }
        cout << endl;
    }
    
    return 0;
}

C++: #include <iostream>
#include <vector>
#include <queue>
#include <cstdio>
using namespace std;
 
int n;
vector <int> G[101];
queue <int> Q;
int  d[100];
int  dis[101];
 
 
int visit(int x){
  int t,i;
   
  Q.push(x);
  dis[x] = 0;
  d[x] = 1;
 
  while(Q.empty() == false) {
     
    // cout << "start Q" <<endl;
 
    t = Q.front();
    Q.pop();
 
    for(i=0; i<G[t].size();i++) {
      if(d[G[t][i]] == 0 ) {
    d[G[t][i]] = 1;
    dis[G[t][i]] = dis[t] + 1;
 
    Q.push(G[t][i]);
      }
 
    }
  }
}
     
int main() {
   
  int i,j,k,l,u,a,t;
   
   
  scanf("%d",&n);
 
   
   
  for(i=0;i<n;i++){
    d[i] = 0;
    dis[i] = -1;
    scanf("%d %d ",&k,&u);
     
    for(j=0;j<u;j++) {
      scanf("%d",&a);
      G[k-1].push_back(a-1);
      // printf("G[%d][%d] = 1\n",i,k-1);
    }
  }
   
   
  visit(0);
 
   
 
  for(i=0;i<n;i++) cout << i+1<<" " << dis[i] <<endl;
 
 
 
  return 0;
 
     
     
}