Go: package main

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

type Pair struct {
	v int
	d int
}

type Queue []Pair

func (q *Queue) push(v Pair) {
	*q = append(*q, v)
}

func (q *Queue) pop() Pair {
	v := (*q)[0]
	*q = (*q)[1:]
	return v
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	nVerts := scanInt(sc)
	graph := make([][]int, nVerts+1)

	for i := 0; i < nVerts; i++ {
		u := scanInt(sc)
		nDegrees := scanInt(sc)

		graph[u] = make([]int, nDegrees)
		for d := 0; d < nDegrees; d++ {
			graph[u][d] = scanInt(sc)
		}
	}

	paths := make([]int, nVerts+1)

	queue := Queue(make([]Pair, 0))
	queue.push(Pair{1, 1})
	paths[1] = 1

	for len(queue) > 0 {
		p := queue.pop()
		d := p.d + 1
		for _, v := range graph[p.v] {
			if paths[v] == 0 {
				paths[v] = d
				queue.push(Pair{v, d})
			}
		}
	}

	w := bufio.NewWriter(os.Stdout)
	for i := 1; i <= nVerts; i++ {
		fmt.Fprintf(w, "%d %d\n", i, paths[i]-1)
	}
	w.Flush()
}

func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	v, _ := strconv.Atoi(sc.Text())
	return v
}

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

using namespace std;
static const int N=100;
static const int INFTY=(1<<21);

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<bits/stdc++.h>
using namespace std;
typedef pair<int,int> P;
int n;
int a[105][105];
int d[105];
void bfs(int x){
  d[x]=0;
  queue<P > q;
  int y=x;
  for(int i=1;i<=n;i++){
    if(a[y][i])q.push(P(i,d[y]+1));
  }
  while(!q.empty()){
    P p=q.front();q.pop();
    y=p.first;
    if(d[y]!=-1)continue;
    d[y]=p.second;
    for(int i=1;i<=n;i++){
      if(a[y][i])q.push(P(i,d[y]+1));
    }
  }
}
int main(){
  for(int i=0;i<105;i++){
    d[i]=-1;
  }
  cin >> n;
  for(int i=0;i<n;i++){
    int u,m;
    cin >> u >> m;
    for(int j=0;j<m;j++){
      int v;
      cin >> v;
      a[u][v]=1;
    }
  }
  bfs(1);
  for(int i=1;i<=n;i++){
    cout << i<< " " <<d[i] << endl;
  }
  return 0;
}

C++: //＃いんｃぅで＜ｓｔぢお。ｈ＞
#include<stdio.h>
#include<iostream>
using namespace std;
int n=0,u=0;
int k[101],v[101][101],d[101];
int lptr=0,fptr=0;//lptr==enqueue,fptr==dequeue...
int t1[10000];
int s1[10000];
int c=0;//current
int nx=sizeof(t1)/sizeof(t1[0]);
void Enqueue(int s,int t){
	t1[lptr]=t;
	s1[lptr]=s;
	lptr=(lptr+1)%nx;
}
void bfs(int l){
	while(fptr!=lptr){
		l=t1[fptr];
		c=s1[fptr];
		fptr=(fptr+1)%nx;
		if(d[l]!=-1){
			continue;
		}
		for(int i=0;i<k[l];i++){
			if(v[l][i]){
				Enqueue(c+1,v[l][i]);
			}
		}
		d[l]=++c;
	}
}
int main(void){
	cin>>n;
	for(int i=0;i<n;i++){
		cin>>u;
		cin>>k[u];
		for(int j=0;j<k[u];j++){
			cin>>v[u][j];
		}
	}
	Enqueue(-1,1);
	for(int i=0;i<n+1;i++){
		d[i]=-1;
	}
	bfs(0);
	
	for(int i=1;i<n+1;i++){
		cout<<i<<" "<<d[i]<<endl;
	}
	
	return 0;
}

C++: /**
 * Bredth first search.
 */

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

void bfs(int n, int dd) {
	int k = adj[n][0];
	d[n] = dd++;
	for (int j=1;j<=k;j++) {
		bfs(adj[n][j], dd);
	}
}

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

	bfs(1, 0);

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

	return 0;
}

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

#include <cassert>
#include <climits>

#include <string.h>

#include <vector>
#include <map>
#include <stack>
#include <deque>

enum Color
{
    kWhite,
    kGray,
    kBlack,
};

int n;
int start_vertex = 0;
std::vector< std::vector<int> > matrix;
std::vector<Color> c;
std::vector<int> d;

void breadthFirstSearch()
{
    for (int i = 0; i < n;++i)
    {
        c.push_back(kWhite);
        d.push_back(-1);
    }

    std::deque<int> tmp_queue;
    tmp_queue.push_back(start_vertex);
    c[start_vertex] = kGray;
    d[start_vertex] = 0;

    while (! tmp_queue.empty())
    {
        int current = tmp_queue.front();
        tmp_queue.pop_front();
        c[start_vertex] = kBlack;

        std::vector<int> line = matrix[current];
        for (int i = 0; i < line.size(); ++i)
        {
            if (line[i] > 0 && c[i] == kWhite)
            {
                tmp_queue.push_back(i);
                c[i] = kGray;
                d[i] = d[current] + 1;
            }
        }
    }
}

int main()
{
    std::cin >> n;
    for (int i = 0; i < n; ++i)
    {
        std::vector<int> line;
        for (int j = 0; j < n; ++j)
        {
            line.push_back(0);
        }
        matrix.push_back(line);
    }

    for (int i = 0; i < n; ++i)
    {
        int u;
        int k;

        std::cin >> u;
        std::cin >> k;

        for (int j = 0; j < k; ++j)
        {
            int tmp;
            std::cin >> tmp;
            matrix[u - 1][tmp - 1] = 1;
        }
    }

    breadthFirstSearch();

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

    return 0;
}

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

vector<int> bfs(vector<vector<int>> &adj_list)
{
    vector<int> res(adj_list.size(), -1);
    vector<bool> visit(adj_list.size(), 0);
    queue<int> q;
    q.push(0);
    visit[0] = 1;
    res[0] = 0;

    while (!q.empty())
    {
        int u = q.front();
        q.pop();
        for (int i = 0; i < adj_list[u].size(); i++)
        {
            int v = adj_list[u][i];
            if (visit[v] == 0)
            {
                visit[v] = 1;
                res[v] = res[u] + 1;
                q.push(v);
            }
        }
    }

    return res;
}

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

    vector<vector<int>> adj_list(n);
    for (int i = 0; i < n; i++)
    {
        int id, k;
        cin >> id >> k;
        for (int j = 0; j < k; j++)
        {
            int u;
            cin >> u;
            adj_list[id - 1].push_back(u - 1);
        }
    }

    // for (int i = 0; i < n; i++)
    // {
    //     for (int j = 0; j < adj_list[i].size(); j++)
    //     {
    //         cout << adj_list[i][j] << ", ";
    //     }
    //     cout << endl;
    // }

    vector<int> res = bfs(adj_list);
    for (int i = 0; i < n; i++)
    {
        cout << i + 1 << " " << res[i] << endl;
    }

    return 0;
}