Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

func stringifyArray(arr []int) string {
	return strings.TrimRight(fmt.Sprintf("%+v", arr)[1:], "]")
}

var infty = 1000000000

type nodeKey int

type DirectedGraphNode struct {
	key       nodeKey
	adjacents []*DirectedGraphNode
	visited   bool
	d         int
	parent    *DirectedGraphNode
}

type DirectedGraph struct {
	nodes []DirectedGraphNode
}

func (g *DirectedGraph) setAdjacency(l, r nodeKey) {
	g.nodes[l].adjacents = append(g.nodes[l].adjacents, &g.nodes[r])
}

func newDirectedGraph(nNodes int) *DirectedGraph {
	graph := DirectedGraph{}
	graph.nodes = make([]DirectedGraphNode, nNodes)
	for iNodes := 0; iNodes < nNodes; iNodes++ {
		graph.nodes[iNodes].key = nodeKey(iNodes)

		graph.nodes[iNodes].visited = false
		graph.nodes[iNodes].d = infty
		graph.nodes[iNodes].parent = nil
	}
	return &graph
}

type QueueEntry struct {
	node *DirectedGraphNode
	next *QueueEntry
}

type Queue struct {
	head, tail *QueueEntry
}

func (q *Queue) enqueue(node *DirectedGraphNode) {
	entry := QueueEntry{}
	entry.node = node

	if q.tail == nil {
		q.head = &entry
		q.tail = &entry
		return
	}

	q.tail.next = &entry
	q.tail = q.tail.next
}

func (q *Queue) dequeue() *QueueEntry {
	if q.head == nil {
		return nil
	}
	poped := q.head
	q.head = q.head.next
	if q.head == nil {
		q.tail = nil
	}
	return poped
}

func (q *Queue) isEmpty() bool {
	return q.head == nil
}

func fillDistancesByBreadthFirstSearch(g *DirectedGraph, startNode *DirectedGraphNode) {
	startNode.visited = true
	startNode.d = 0

	queue := Queue{}
	queue.enqueue(startNode)
	for !queue.isEmpty() {
		u := queue.dequeue().node
		for _, adjacent := range u.adjacents {
			if !adjacent.visited {
				adjacent.visited = true
				adjacent.d = u.d + 1
				adjacent.parent = u
				queue.enqueue(adjacent)
			}
		}
		u.visited = true
	}
}

func main() {
	scanner.Split(bufio.ScanWords)

	nNodes := nextInt()
	g := newDirectedGraph(nNodes + 1)

	for iNode := 0; iNode < nNodes; iNode++ {
		nodeKeyLeft := nodeKey(nextInt())
		nAdj := nextInt()
		for iAdj := 0; iAdj < nAdj; iAdj++ {
			nodeKeyRight := nodeKey(nextInt())
			g.setAdjacency(nodeKeyLeft, nodeKeyRight)
		}
	}

	// fmt.Println(g)
	fillDistancesByBreadthFirstSearch(g, &g.nodes[1])
	// fmt.Println(g)

	for iNode := 1; iNode <= nNodes; iNode++ {
		node := g.nodes[iNode]
		distance := node.d
		if distance == infty {
			distance = -1
		}
		fmt.Println(node.key, distance)
	}
}

C++: #include <bits/stdc++.h>
typedef long long ll;
#define ALL(l)  (l).begin(),(l).end()
#define rep(i,n) for(ll (i)=0;(i)<(n);(i)++)
#define rep2(i, s, n) for (ll i = (s); i < (ll)(n); i++)
using namespace std;

//const ll mod =  1000000007;
//const ll maxn = 1000000000;

//---------------------------------------------------------------------------------------------------
using vi = vector<int>; // intの1次元の型に vi という別名をつける
using vll = vector<ll>; // intの1次元の型に vi という別名をつける
using vvll = vector<vll>; // intの2次元の型に vvi という別名をつける
using vs = vector<string>; // stringの1次元の型に vs という別名をつける
using pll = pair<ll, ll>; // これ以降 pii という型名はpair<ll, ll> と同じ意味で使える
//---------------------------------------------------------------------------------------------------


int main() {
   int n;
   cin>>n;
   vi ans(n,-1);
   vi g[n];
   rep(i,n){
       int h,k;
       cin>>h>>k;
       rep(j,k){
           int t;
           cin>>t;
           //cout<<i<<" "<<t-1<<endl;
           g[i].push_back(t-1);
       }
   }
  
   ans.at(0)=0;
   queue<int> q ;
   q.push(0);
   
   while(!q.empty()){
      int from=q.front();
      q.pop();
      for(int to : g[from]){
          if(ans.at(to)!=-1)continue;
          ans.at(to)=ans.at(from)+1;
          q.push(to);
      }
   }
   rep(i,n){
       cout<<i+1<<" "<<ans.at(i)<<endl;
   }
}

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

const int nIMPOS = -1;
struct StDist
{
  int m_nDist;
  int m_nFromMeTo;

  StDist(int nDist) : m_nDist(nDist), m_nFromMeTo(0)
  { }
};

void fnInput(vector<vector<int>>& rvvnAdjcy, vector<StDist>& rvoDist)
{
  int nxSiz;
  cin >> nxSiz;

  rvvnAdjcy.resize(nxSiz + 1, vector<int>(nxSiz + 1, 0));
  for (int i = 0; i < nxSiz; ++i)
  {
    int nx, nySiz;
    cin >> nx >> nySiz;
    for (int j = 0; j < nySiz; ++j)
    {
      int ny;
      cin >> ny;
      rvvnAdjcy[nx][ny] = 1;
    }
  }
  StDist oDist(nIMPOS);
  rvoDist.resize(nxSiz + 1, oDist);
}

void fnBreadthFirstSearch(const vector<vector<int>>& cnrvvnAdjcy, 
                          queue<int>& rqnBFSrch, vector<StDist>& rvoDist)
{
  while (rqnBFSrch.size())
  {
    int nx = rqnBFSrch.front(); rqnBFSrch.pop();
    if (rvoDist[nx].m_nDist == nIMPOS)  continue;
    if (rvoDist[nx].m_nFromMeTo == 1 )  continue; 

    rvoDist[nx].m_nFromMeTo = 1;
    for (int ny = 1; ny < cnrvvnAdjcy[nx].size(); ++ny)
      if (cnrvvnAdjcy[nx][ny] == 1)
      {
        int nDist = rvoDist[nx].m_nDist + 1;
        if (rvoDist[ny].m_nDist == nIMPOS)
          rvoDist[ny].m_nDist = nDist;
        else
          rvoDist[ny].m_nDist = min(rvoDist[ny].m_nDist, nDist);

        rqnBFSrch.push(ny);
      }
  }
}

void fnResult(const vector<StDist>& cnrvoDist)
{
  for (int i = 1; i < cnrvoDist.size(); ++i)
    cout << i <<  " " << cnrvoDist[i].m_nDist << endl;
}

int main()
{
  cin.tie(0);
  ios::sync_with_stdio(false);
  vector<vector<int>> vvnAdjcy;
  queue<int>  qnBFSrch;
  vector<StDist> voDist;

  fnInput(vvnAdjcy, voDist);

  voDist[1].m_nDist = 0;
  qnBFSrch.push(1);
  fnBreadthFirstSearch(vvnAdjcy, qnBFSrch, voDist);
  fnResult(voDist);

  return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<queue>
#define Lens 105
using namespace std;
int N;
int A[Lens][Lens];
int d[Lens];
char c[Lens];
queue<int> Q;

int main()
{
	cin >> N;
	for (int i = 1; i <= N; i++)
	{
		int k, n;
		cin >> k >> n;
		c[k] = 'w';
		for (int i = 0; i < n; i++)
		{
			int j;
			cin >> j;
			Q.push(j);
			A[k][j] = 1;
		}
	}
	int j = Q.front();
	for (int i = 1; i <= N; i++)
	{
		while (A[i][j] == 1 && c[j] == 'w')
		{
			Q.pop();
			d[j] = d[i] + 1;
			c[j] = 'g';
			if (Q.size() == 0)
				break;
			j = Q.front();
			while (c[j] == 'g')
			{
				Q.pop();
				if (Q.size() == 0)
					break;
				j = Q.front();
			}

		}

	}
	for (int i = 1; i <= N; i++)
	{
		cout << i << ' ' << d[i] << endl;
	}
	return 0;
}

C++: #include<bits/stdc++.h>

using namespace std;

vector<int> G[110];

const int INF=1e9;

int d[110];
bool used[110];

void bfs(int x)
{
    fill(d,d+110,INF);
    d[x]=0;

    queue<pair<int,int> > q;

    q.push(make_pair(0,x));

    used[x]=true;

    while(!q.empty())
    {
        pair<int,int> tmp=q.front();q.pop();

        int dd=tmp.first,now=tmp.second;
        for(int i=0;i<G[now].size();i++)
        {
            if(!used[G[now][i]])
            {
                d[G[now][i]]=dd+1;
                q.push(make_pair(dd+1,G[now][i]));
                used[G[now][i]]=true;
            }
        }
    }
}


int main()
{
    int n;

    cin>>n;

    for(int i=0;i<n;i++)
    {
        int a,b,c;

        cin>>a>>b;

        for(int j=0;j<b;j++)
        {
            cin>>c;

            G[a].push_back(c);
        }
    }

    bfs(1);

    for(int i=1;i<=n;i++)
    {
        cout<<i<<" ";

        if(d[i]==INF)
        {
            cout<<"-1";
        }else
        {
            cout<<d[i];
        }
        cout<<endl;
    }

    return 0;
}