Go: package main

import (
	"fmt"
	"os"
	"bufio"
	"strconv"
	"container/list"
)

const MaxNode int = 100

var d []int
var A [][]int
var N int
var l *list.List

func bfs(u int) {
	d[u] = 0
	l.PushBack(u)
	for ;l.Len() != 0; {
		u = l.Front().Value.(int)
		l.Remove(l.Front())
		for v:=0; v<N; v++ {
			if A[u][v] == 0 {
				continue
			}
			if d[v] != -1 {
				continue
			}
			d[v] = d[u] + 1
			l.PushBack(v)
		}
	}
}


func nextInt(scanner *bufio.Scanner) int {
	scanner.Scan()
	num, _ := strconv.Atoi(scanner.Text())
	return num
}

func print() {
	for i:=0; i<N; i++ {
		fmt.Printf("%d %d\n", i+1, d[i])
	}
}

func initVariable() {
	d = make([]int, MaxNode)
	A = make([][]int, MaxNode)
	l = list.New()
	for i:=0; i<MaxNode; i++ {
		A[i] = make([]int, MaxNode)
		d[i] = -1
	}
}


func main() {
	initVariable()
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	N = nextInt(scanner)
	for i:=0; i<N; i++ {
		idx := nextInt(scanner)
		cnt := nextInt(scanner)
		for j:=0; j<cnt; j++ {
			node := nextInt(scanner)
			A[idx-1][node-1] = 1 
		}
	}
	bfs(0)
	print()
}

C++: #include <iostream>
#include <vector>
#include <unordered_map>
#include <set>
#include <queue>
//#include "../cxx-prettyprint/prettyprint.hpp"


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

    std::unordered_map<int, std::vector<int>> Adj(n);

    for (int i = 0; i < n; i ++) {
        int u, k;
        std::cin >> u >> k;
        std::vector<int> V(k);
        for (int& v : V) {
            std::cin >> v;
        }
        Adj[u] = V;
    }

    std::set<int> nodes_unvisited;
    std::unordered_map<int, int> distances;
    for (int i = 1; i <= n; i ++) {
        nodes_unvisited.insert(i);
        distances[i] = -1;
    }

    nodes_unvisited.erase(1);
    distances[1] = 0;
    std::queue<int> queue;
    queue.push(1);

    while (!queue.empty()) {
        int u = queue.front();
        queue.pop();
        for (int v : Adj[u]) {
            if (nodes_unvisited.find(v) != nodes_unvisited.end()) {
                nodes_unvisited.erase(v);
                distances[v] = distances[u] + 1;
                queue.push(v);
            }
        }
    }

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

C++: #include<bits/stdc++.h>
using namespace std;
#define clr(a,b) memset(a,b,sizeof(a))
int n;
int v,k,ttm;
vector<int> graph[105];
int dis[105];//到其他点的距离
int vis[105];//纪律顶点是否被访问
void bfs(int u)
{
    queue<int> qu;
    qu.push(u);
    dis[u]=0;
    vis[u]=1;
    while(!qu.empty())
    {
        int v=qu.front();qu.pop();
        for(int i:graph[v])
        {
            if(vis[i]){continue;}
            vis[i]=1;qu.push(i);
            dis[i]=dis[v]+1;
        }
    }
}
int main()
{
    clr(vis,0);
    cin>>n;
    for(int i=0;i<n;++i)
    {
        cin>>v>>k;
        while(k--)
        {
            cin>>ttm;
            graph[v].push_back(ttm);//连接的点
        }
    }
    bfs(1);
     cout<<1<<" "<<dis[1]<<endl;
    for(int i=1;i<=n;++i)
    {
         cout<<i<<" "<<(dis[i]?dis[i]:-1)<<endl;
    }
    return 0;
}

C++: #include <stdio.h>
#include <algorithm>

using namespace std;

struct Info{
	Info(){m_node = m_distance = 0;}
	Info(int node,int distance){
		m_node = node;
		m_distance = distance;
	}
	int m_node,m_distance;
};

class InfoQueue{
public:
	InfoQueue(){
		info = new Info[10000];
		num_of_data = head = tail = 0;
	}
	bool isEmpty(){
		return num_of_data == 0;
	}
	void enqueue(Info data){
		info[tail] = data;
		tail = (tail+1)%10000;
		num_of_data++;
	}
	Info dequeue(){
		Info ret = info[head];
		head = (head+1)%10000;
		num_of_data--;
		return ret;
	}
private:
	Info* info;
	int head,tail,num_of_data;
};


int main(){

	int n,row,col,num;
	scanf("%d",&n);

	int table[n+1][n+1];
	int check_table[n+1];

	for(int i=1;i<=n;i++){
		check_table[i] = -1;
		for(int k=1;k<=n;k++)table[i][k] = 0;
	}

	for(int i=1;i<=n;i++){
		scanf("%d %d",&row,&num);
		for(int k=1;k<=num;k++){
			scanf("%d",&col);
			table[row][col]=1;
		}
	}

	check_table[1] = 0;

	InfoQueue Q;
	Q.enqueue(Info(1,0));

	Info tmp;
	while(!Q.isEmpty()){
		tmp = Q.dequeue();
		for(int i=1;i<=n;i++){
			if(table[tmp.m_node][i]==1 && check_table[i] == -1){
				check_table[i] = tmp.m_distance+1;
				Q.enqueue(Info(i,tmp.m_distance+1));
			}
		}
	}

	for(int i=1;i<=n;i++){
		printf("%d %d\n",i,check_table[i]);
	}

    return 0;
}

C++: //ALDS1_11C
#include <iostream>
#include <vector>
#include <queue>
using namespace std;

static const int N=100;
static const int INF=(1<<21);
int n,d[N];
vector<vector<int> > M(N,vector<int>(N));

void bfs(int s){
 queue<int> q;
 q.push(s);
 for(int i=0;i<n;i++) d[i]=INF;
 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]!=INF) continue;
   d[v]=d[u]+1;
   q.push(v);
  }
 }
 for(int i=0;i<n;i++){
  cout<<i+1<<" "<<((d[i]==INF) ? (-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);
 return 0;
}

C++: #include<iostream>
#include<queue>
#define N 100
#define INFTY (1<<21)
using namespace std;

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++)
    {
      for(int j=0;j<n;j++) M[i][j]=0;
    }

  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);

  return 0;
}

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

using namespace std;
#define N 100
#define INF 2000000

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

void bfs(int s){
	int i,u,v;

	queue<int> q;
	q.push(s);
	for(i=0;i<n;i++){
		d[i] = INF;
	}

	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] != INF) continue;
			d[v] = d[u] + 1;
			q.push(v);
		}
	}
	for(i=0;i<n;i++){
		if(d[i] == INF){
			printf("%d -1\n",i+1);
		}else{
			printf("%d %d\n",i+1,d[i]);
		}
	}
}


int main(void){
	int i,j,u,k,v;

	scanf("%d",&n);

	for(i=0;i<n;i++){
		for(j=0;j<n;j++){
			M[i][j] = 0;
		}
	}

	for(i=0;i<n;i++){
		scanf("%d%d",&u,&k);
		u--;
		for(j=0;j<k;j++){
			scanf("%d",&v);
			v--;
			M[u][v] = 1;
		}
	}

	bfs(0);

	return 0;
}

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

using namespace std;

int D[100100];//始点からの距離を入れる
int g[1001][1001]={{0}};//要素を0で初期化
void bfs(int src,int n){//srcは開始位置この場合だと頂点1だから0
  cerr << "bfs_root = " << src << endl;
  queue<int> Q;
  Q.push(src);
  D[src] = 0;
  while (! Q.empty()  ){
    int cur = Q.front();
    Q.pop();
    // cerr << "visiting_" << cur << " " <<D[cur] <<endl;
    for(int dst= 0; dst < n; dst++){
      if(g[cur][dst]==1 && D[dst]==0){
        D[dst]=D[cur]+1;
        Q.push(dst);
      }
    }
  }
}
void ans(int n){
  for (int i = 0; i < n; ++i)
  {
    cout << i+1 <<" "<<D[i]<<endl;
  }

}

int main(){
  // int g[1001][1001]={{0}};//要素を0で初期化
  int n,a,b,c;
  cin >> n;
  for (int i = 0; i < n; ++i)
  {
    cin >> a >> b ;
    for (int i = 0; i < b; ++i)
    {
      cin >> c;
      g[a-1][c-1]=1;/* code */
    }
  }
  bfs(0,n);
  ans(n);
  // for (int i = 0; i < n; ++i)
  // {
  //    for (int j = 0; j < n; ++j)
  //    {
  //     if (j==n-1)
  //     {
  //       cout << g[i][j] << endl;
  //     }else{
  //       cout << g[i][j] <<" ";
  //     }
  //    }
  // }


}