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>
using namespace std;

typedef long long ll;
#define rep(i,n) for(int (i)=0;(i)<(n);(i)++)

const int INF  = 1000001;

int main() {
    int n; cin>>n;
    
    vector<int> to[100];
    rep(i,n){
        int a,m;
        cin>>a>>m;
        --a;
        
        rep(j,m){
            int b;cin>>b;
            --b;
            to[a].push_back(b);
//            to[b].push_back(a);
//          cout<<a<<" "<<b<<endl;
        }
    }

    queue<int> q;
    vector<int> dist(n, INF);
    dist[0]=0;
    q.push(0);

    while(!q.empty()){
        int v = q.front(); q.pop();
      for(int u : to[v]){
        if (dist[u] != INF) continue;
            dist[u] = dist[v] + 1;
            q.push(u);
//          cout<<u<<" "<<dist[u]<<endl;
        }
    }
  
    rep(i,n){
        int res1 = i+1;
        int res2 = dist[i];
        if(i == 0)res2 = 0;
        if(res2 == INF) res2 = -1;
        cout<<res1<<" "<<res2<<endl;
    }
    
	return 0;
}

C++: #include<iostream>
#include<cstdlib>
using namespace std;
int main() {
	int n, u, k[101], data[101][100]; cin >> n;
	for (int i = 1; i <= n; ++i) {
		cin >> u >> k[i];
		for (int j = 0; j<k[i]; ++j) cin >> data[u][j];
	}
	int queue[10000], head = 0, tail = 1, cost[101];
	for (int i = 2; i <= n; ++i) cost[i] = -1;
	queue[0] = 1; cost[1] = 0;
	while (head != tail) {
		int val = queue[head++];
		for (int i = 0; i < k[val]; ++i) {
			if (cost[data[val][i]] == -1) {
				queue[tail++] = data[val][i];
				cost[data[val][i]] = cost[val] + 1;
			}
		}
	}
	for (int i = 1; i <= n; ++i) cout << i << " " << cost[i] << endl;
	return 0;
}

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)        continue; 

    rvoDist[nx].m_nFromMeTo = 1;
    for (int ny = 1; ny < cnrvvnAdjcy[nx].size(); ++ny)
      if (cnrvvnAdjcy[nx][ny])
      {
        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 <vector>
#include <queue>
 
using namespace std;
static const int INF = 1e9;
static const int SIZE = 101;
typedef pair<int, int> P;
 
int d[SIZE];
vector<int> G[SIZE];
 
void solve()
{
    int n;
    cin >> n;
    for (int i = 0; i < n; ++i)
    {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; ++j)
        {
            int v;
            cin >> v;
            G[u].push_back(v);
        }
    }
    for (int i = 0; i < SIZE; ++i)
    {
        d[i] = INF;
    }
    d[1] = 0;
    queue<P> que;
    que.push(P(0, 1));
    while (!que.empty())
    {
        P p = que.front();
        que.pop();
        int v = p.second;
        for (int i = 0; i < G[v].size(); ++i)
        {
            int to = G[v][i];
            if (d[to] > p.first + 1)
            {
                d[to] = p.first + 1;
                que.push(P(d[to], to));
            }
        }
    }
    for (int i = 1; i <= n; ++i)
    {
        if (d[i] == INF)
        {
            cout << i << " " << -1 << endl;
        }
        else
        {
            cout << i << " " << d[i] << endl;
        }
    }
}
 
int main()
{
    solve();
    return(0);
}