Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

//util
var sc = bufio.NewScanner(os.Stdin)

func nextStr() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func printList(list []int) {
	n := len(list)
	buf := bufio.NewWriter(os.Stdout)
	for _, v := range list[0 : n-1] {
		buf.Write([]byte(fmt.Sprintf("%d ", v)))
	}
	buf.Write([]byte(fmt.Sprintf("%d\n", list[n-1])))
	buf.Flush()
}

func max(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func min(a, b int) int {
	if a > b {
		return b
	} else {
		return a
	}
}

//solve
const INFTY = (1 << 21)
const MAX = 100
const WHITE = 0
const GRAY = 1
const BLACK = 2

var time, n int

//隣接行列
var M [MAX][MAX]int

//d[i]: 頂点1から頂点iまでの距離
var color, d [MAX]int

func bfs(s int) {
	var q []int
	q = append(q, s)
	for i := 0; i < n; i++ {
		d[i] = INFTY
	}
	//sは開始点なので、0をいれる
	d[s] = 0

	//キューが空になるまで、以下を繰り返す
	for len(q) > 0 {
		u := q[0]
		q = q[1:]
		for v := 0; v < n; v++ {
			if M[u][v] == 0 {
				continue
			}
			if d[v] != INFTY {
				continue
			}
			d[v] = d[u] + 1
			q = append(q, v)
		}
	}

	for i := 0; i < n; i++ {
		fmt.Printf("%d ", i+1)
		if d[i] == INFTY {
			fmt.Printf("%d\n", -1)
		} else {
			fmt.Printf("%d\n", d[i])
		}
	}
}

func main() {
	sc.Split(bufio.ScanWords)
	n = nextInt()
	for i := 0; i < n; i++ {
		u, k := nextInt(), nextInt()
		M[u-1][u-1] = 0

		//fmt.Println(u, k)
		if k > 0 {
			for j := 0; j < k; j++ {

				v := nextInt()
				M[u-1][v-1] = 1

			}
		}

	}

	bfs(0)

}

C++: #include <iostream>
#include <queue>
using namespace std;
int n,G[101][101];
int d[101];
int dis;
void bfs(){
    queue<int>q;
    int u=1;
    q.push(u);
    d[u]=dis;
    while(!q.empty()){
        u=q.front();
        dis=d[u]+1;
        for(int i=1;i<=n;i++)
        {
            if(G[u][i]==1 && d[i]==-1)
            {
                q.push(i);
                d[i]=dis;
            }
        }
        q.pop();
    }
}
int main()
{
    int u,k,v;
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        d[i]=-1;
        for(int j=1;j<=n;j++)
            G[i][j]=0;
    }
    for(int i=0;i<n;i++)
    {
        cin>>u>>k;
        for(int j=0;j<k;j++)
        {
            cin>>v;
            G[u][v]=1;
        }
    }
    dis=0;
    bfs();
    for(int i=1;i<=n;i++)
        cout<<i<<' '<<d[i]<<endl;
    return 0;
}

C++: //16D8103013E Sen Shunkou
#include<iostream>
#include<queue>
int n;
int cnt=0;

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

    int cnt=0;
    int A[100][100];
    int dis_min[n];
    bool visited[n];

    for(int i=0;i<100;i++){
        for(int j=0;j<100;j++){
            A[i][j]=0;
        }
    }

    for(int i=0;i<n;i++){
        std::cin>>A[i][0];
        std::cin>>A[i][1];
        for(int j=0;j<A[i][1];j++){
            std::cin>>A[i][j+2];
        }
    }

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

    //initialization
    std::queue<int> que;
    que.push(0);
    //std::cout<<"\n"<<que.front()<<"\n";
    //std::cout<<que.size()<<"\n\n";

    while(!que.empty()){
        int q=que.size();
        for(int k=0;k<q;k++){
            //std::cout<<"quesize"<<que.size()<<"\n";
            int i=que.front();
            que.pop();
            visited[i]=true;
            dis_min[i]=cnt;
            //std::cout<<i<<"cnt"<<cnt<<"\n";
            if(A[i][1]!=0){
                for(int j=0;j<A[i][1];j++){
                    if(visited[A[i][j+2]-1]!=true){
                        visited[A[i][j+2]-1]=true;
                        que.push(A[i][j+2]-1);
                        //std::cout<<A[i][j+2]-1<<"\n";
                    }
                }
            }
        }
        cnt++;
        //std::cout<<"cnt="<<cnt<<"\n";
    }

    //std::cout<<"===========\n";

    //output
    for(int i=0;i<n;i++){
        std::cout<<i+1<<" "<<dis_min[i]<<std::endl;
    }

    return 0;
}

C++: /**
 * Bredth first search.
 * graphs could be circular.
 */

#include <iostream>
using namespace std;
const int N = 101;
int adj[N][N] = {0};
int d[N] = {0};
int s[N] = {0};

void bfs(int n, int dd) {
	int k = adj[n][0];
	int kk = 0;
	for (int j=1;j<=k;j++) {
		int nn = adj[n][j];
		if (d[nn] != -1) continue;
		d[nn]=dd;
		s[kk++]=nn;
	}

	for (int j=0;j<kk;j++)
	{
		bfs(s[j], dd+1);
	}
}

int main()
{
	int n;
	cin >> n;
	for (int i=1;i<=n;i++){
		int j, k;
		cin >> j >> k;
		d[j]=-1;
		adj[j][0]=k;
		for (int m=1;m<=k;m++) {
			int a;
			cin >> a;
			adj[j][m]=a;
		}
	}

	d[1]=0;

	bfs(1, 1);

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

	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::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<bits/stdc++.h>

using namespace std;

typedef vector<int> vec;
typedef vector<vec> Graph;

Graph G(110);

int main()
{
	int n;
	scanf("%d",&n);
	for(int i=0;i<n;i++)
	{
		int u,t;
		scanf("%d%d",&u,&t);
		for(int j=0;j<t;j++)
		{
			int v;
			scanf("%d",&v);
			G[u].push_back(v);
		}
	}
	queue<int> que;
	int d[110];
	fill(d+1,d+n+1,-1);
	d[1]=0;
	que.push(1);
	while(!que.empty())
	{
		int t=que.front();que.pop();
		for(int i=0;i<G[t].size();i++)
			if(d[G[t][i]]==-1||d[t]+1<d[G[t][i]])
			{
				d[G[t][i]]=d[t]+1;
				que.push(G[t][i]);
			}
	}
	for(int i=1;i<=n;i++)
		printf("%d %d\n",i,d[i]);
	return 0;
}