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 ll = long long;
using namespace std;
#define _overload3(_1, _2, _3, name, ...) name
#define _rep(i, n) repi(i, 0, n)
#define repi(i, a, b) for(int i = int(a); i < int(b); ++i)
#define rep(...) _overload3(__VA_ARGS__, repi, _rep, )(__VA_ARGS__)
const long long INFLL = 1LL << 60;
const int INFINT = 1 << 30;
const long long MOD = 1e9 + 7;

vector<vector<int>> G(101, vector<int>(0));
vector<int> c(101, 0);
vector<int> d(101, 0);
vector<int> f(101, 0);

template <class T> void vecout(T V) {
    auto t = V.begin();
    *t++;
    while(t != V.end()) {
        cout << " " << *t++;
        // if(t != V.end()) cout << " ";
    }
    cout << endl;
};

int t = 0;
void dfs(int i) {
    if(c[i]) return;
    c[i] = 1;
    d[i] = ++t;
    for(auto e : G[i])
        dfs(e);
    f[i] = ++t;
}

class node {
  public:
    int dist = -1;
    vector<int> nex;
};

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n, u, k, a;
    cin >> n;
    vector<node> Node(n + 1);
    queue<int> Q;
    rep(i, n) {
        cin >> u >> k;
        rep(j, k) {
            cin >> a;
            Node.at(u).nex.push_back(a);
        }
    }
    Node[1].dist = 0;
    Q.push(1);

    while(!Q.empty()) {
        int v = Q.front();
        Q.pop();
        for(auto e : Node[v].nex) {
            if(Node[e].dist > -1) continue;
            Node[e].dist = Node[v].dist + 1;
            Q.push(e);
        }
    }

    rep(i, 1, n + 1) cout << i << " " << Node[i].dist << "\n";
}

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

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

  StDist(int nDist) : m_nDist(nDist), m_nDmy(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();

    for (int ny = 1; ny < cnrvvnAdjcy[nx].size(); ++ny)
    {
      if (!cnrvvnAdjcy[nx][ny])          continue;
      if (rvoDist[ny].m_nDist != nIMPOS) continue; 

      int nDist = rvoDist[nx].m_nDist + 1;
      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<bits/stdc++.h>
using namespace std;
typedef long long int ll;

int t[110];	
vector<int> a[110];

void deep(int n,int time) {
	time++;
	for (int i = 0; i < a[n].size(); i++) {
		if (t[a[n][i]] >time) {
			t[a[n][i]] = time;
			deep(a[n][i],time);
		}
		else if (t[a[n][i]] == -1) {
			t[a[n][i]] = time;
			deep(a[n][i], time);
		}
	}
}


int main() {
	ios::sync_with_stdio(false); cin.tie(0);
	
	int N; cin >> N;
	int u, k, v;
	fill(t, t + 110, -1);
	t[1] = 0;
	for (int i = 0; i < N; i++) {
		cin >> u >> k;
		for (int j = 0; j < k; j++) {
			cin >> v;
			a[u].push_back(v);
		}
	}
	deep(1, 0);
	for (int i = 1; i <= N; i++) {
		cout << i << " " << t[i] << endl;
	}
}

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

#define N 100
#define INFTY 1000000

int M[N][N],d[N];
int i,j,n,u,k,v;

void bfs(int s){

  queue <int> Q;

  for( i = 0; i < N; i++ ) d[i] = INFTY;
  

  d[s] = 0;
  Q.push(s);
    
  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( i = 0; i < n; i++ ){
    cout << i+1 << " ";
    if ( d[i] == INFTY ) cout << -1;
    else cout << d[i];
    cout << endl;
  }

}


int main(){
  for( i = 0; i < n; i++ ){
    for( j = 0; j < n; j++ ) M[u][v] = 0;
  }
  cin >> n;
  for( i = 0; i < n; i++ ){
    cin >> u;
    u--;
    cin >> k;
    for( j = 0; j < k; j++ ){
      cin >> v;
      v--;
      M[u][v] = 1;
    }
  }
  bfs(0);
  
  return 0;
}