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>
using namespace std;
static const int INFTY=(1<<21);
static const int N=100;
int n,M[N][N],d[N];

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

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

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

  return 0;
}

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

class Graph{
private:





 class Node{
 private:
  unsigned long node_id_;
  long depth_;

  std::vector<unsigned long> adjnodes_;
 public:

  Node(const unsigned long node_id,const std::vector<unsigned long> &adjnodes)
      : node_id_(node_id),
        depth_(-1),
        adjnodes_(adjnodes){
   if(node_id_ == 1) depth_ = 0;
  };

  bool isDepth(){
   if(depth_ == -1) return true;

   return false;
  };

  void CheckNode(std::queue<unsigned long>& queue_nextnode,const std::vector<Node*>& node){
   for(unsigned long adjnode_i = 0, adjnode_max = adjnodes_.size(); adjnode_i < adjnode_max; ++adjnode_i){
    unsigned long nextadjnode = adjnodes_[adjnode_i]-1;
    if(node[nextadjnode]->isDepth()){
     node[nextadjnode]->depth_ = depth_ + 1;
     queue_nextnode.push(nextadjnode);
    }
   }
  };

  void display(){
   std::cout << node_id_ << " ";
   std::cout << depth_ << " ";
   std::cout << std::endl;
  };
 protected:
 };





 std::vector<Node*> node_;

public:
 Graph(unsigned long node_max) : node_(std::vector<Node*>(node_max, 0)){};
 void CreateNode(const unsigned long node_i,const unsigned long node_id,const std::vector<unsigned long>& adjnodes){
  node_[node_i] = new Node(node_id, adjnodes);
 };

 void BreadthFirstSearch(){
  if(node_.empty()) return ;

  std::queue<unsigned long> queue_nextnode;
  queue_nextnode.push(0);
  while(!queue_nextnode.empty()){
   unsigned long nextnode = queue_nextnode.front();
   queue_nextnode.pop();
   node_[nextnode]->CheckNode(queue_nextnode, node_);

  }

 };

 void display(){
  for(unsigned long node_i = 0, node_max = node_.size(); node_i < node_max; ++node_i){
   node_[node_i]->display();
  }
 };
protected:

};


int main(){

 unsigned long node_max = 0; std::cin >> node_max;

 /*
  *  ノード数分の記憶領域を確保する。
  */
 Graph graph(node_max);

 /*
  *入力はテキスト。
  *入力は一行目に    [ノード数]
  *      二行目以降  [頂点id 接続ノード数 接続ノード1 接続ノード2 ...]
  */
 for(unsigned long node_i = 0; node_i < node_max; ++node_i){
  unsigned long node_id = 0; std::cin >> node_id;
  unsigned long adjnode_max = 0; std::cin >> adjnode_max;
  std::vector<unsigned long> adjnodes(std::vector<unsigned long>(adjnode_max, 0));
  for(unsigned long adjnode_i = 0; adjnode_i < adjnode_max; ++adjnode_i){
   std::cin >> adjnodes[adjnode_i];
  }

  graph.CreateNode(node_i, node_id, adjnodes);
 }

 graph.BreadthFirstSearch();
 graph.display();

 return 0;
};

C++: include <iostream>
#include <queue>
using namespace std;
typedef long long ll;
#define int ll

int g[105][105], d[105], n;

void bfs() {
  queue<int> q;
  q.push(0);
  fill(d, d + n, -1);
  d[0] = 0; 

  while(!q.empty()) {
    int que = q.front();
    q.pop();
    for (int i = 0; i < n; i++) {
      if (g[que][i] && d[i] == -1) {
        d[i] = d[que] + 1;
        q.push(i);
      }
    }
  }
}

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

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

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

int A[100][100],dk[100],L[100];

void BFS(int n,int u){
    int k;
    queue<int> Q;
    Q.push(u);
    dk[u]=0;L[u]=1;
    while(!Q.empty()){
        k=Q.front();Q.pop();
        for(int i=0;i<n;i++){
            if(A[k][i]==1&&L[i]==-1){
                Q.push(i);L[i]=1;dk[i]=dk[k]+1;
            }
        }
    }
}

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

    for(int i=0;i<n;i++){
        scanf("%d %d",&v,&u);
        v--;
        for(int j=0;j<u;j++){
            scanf("%d",&k);
            k--;
            A[v][k]=1;
        }
    }
    BFS(n,0);
    for(int i=0;i<n;i++){
        printf("%d %d\n",i+1,dk[i]);
    }
}