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 <stdio.h>
#include <stdint.h>
#include <iostream>
#include <fstream>
#include <cassert>
#include <climits>

#include <vector>
#include <queue>
using namespace std;

#define DEBUG (1)

#if DEBUG
#define DPRINTF(...) do { \
    printf("D(L%d) %s: ", __LINE__, __func__); \
    printf(__VA_ARGS__); \
  } while (false)
#else
#define DPRINTF(...)
#endif // DEBUG


struct Vertex {
  Vertex() :
    id_(-1),
    visited_(0),
    distance_(-1),
    adjNum_(-1) { }

  int id_;
  bool visited_;
  int distance_;
  int adjNum_;
  unique_ptr<int[]> adjIds_;

  void set(int id, vector<int> ids);
  void printInfo();
  void printDistance();
};


void Vertex::set(int id, vector<int> ids)
{
  id_ = id;
  adjNum_ = ids.size();

  if (adjNum_ == 0)
    return;

  adjIds_ = unique_ptr<int[]>(new int[adjNum_]);

  for (int i = 0; i < adjNum_; i++)
    adjIds_[i] = ids[i];
}


void Vertex::printInfo()
{
  DPRINTF("%d %d", id_, adjNum_);
  for (int i = 0; i < adjNum_; i++)
    printf(" %d", adjIds_[i]);
  cout << endl;
}


void Vertex::printDistance()
{
  printf("%d %d\n", id_, distance_);
}


void bfs(Vertex vertices[])
{
  const int startId = 1;
  queue<int> idQueue;

  idQueue.push(startId);

  int distance = 0;

  while (!idQueue.empty()) {

    DPRINTF("queue size %lu\n", idQueue.size());

    const size_t numOfThisDist = idQueue.size();

    for (size_t i = 0; i < numOfThisDist; i++)
    {
      int id = idQueue.front();
      idQueue.pop();

      DPRINTF("%zu  id %d\n", i, id);

      Vertex &vtx = vertices[id];

      if (vtx.visited_)
        continue;

      vtx.visited_ = true;
      vtx.distance_ = distance;

      for (int j = 0; j < vtx.adjNum_; j++)
        idQueue.push(vtx.adjIds_[j]);

    }

    distance++;
  }
}


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

  DPRINTF("%d\n", n);

  // do not use [0], it's empty
  Vertex vertices[n+1];

  for (int i = 1; i <= n; i++)
  {
    int node, adjNum;

    cin >> node >> adjNum;

    vector<int> adjs;

    for (int j = 0; j < adjNum; j++)
    {
      int v;
      cin >> v;
      adjs.push_back(v);
    }

    vertices[i].set(node, adjs);

    cin.ignore();

  }

#ifdef DEBUG
  for (int i = 1; i <= n; i++)
    vertices[i].printInfo();
#endif // DEBUG

  bfs(vertices);

  for (int i = 1; i <= n; i++)
    vertices[i].printDistance();

  return 0;

}

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

using namespace std;

#define N 100
#define 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){
    cin >> u >> k;
    --u;
    for(int j=0; j<k; ++j){
      cin >> v;
      --v;
      M[u][v] = 1;
    }
  }

  bfs(0);



  return 0;
}

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

static const int N=100;
static const int WHITE=0;
static const int GRAY=1;

int n,M[N][N],color[N];
int d[N];
void bfs(int s){
    queue<int> q;
    for(int i=0;i<n;i++){
        d[i]=0;
        color[i]=WHITE;
    }
    color[s]=GRAY;
    q.push(s);
    int u;
    while(!q.empty()){
        u=q.front();q.pop();
        for(int v=0;v<n;v++){
            if(M[u][v]==0)continue;
            if(color[v]==WHITE){
                d[v]=d[u]+1;
                color[v]=GRAY;
                q.push(v);
            }
        }
    }
    for(int i=0;i<n;i++){
        if(i==0)
            cout<<i+1<<" " <<"0"<<endl;
        else
            cout<<i+1<<" "<<((d[i]==0)?(-1):d[i])<<endl;
    }
}
int main()
{
    int u,v,k,i,j;
    scanf("%d",&n);
    for(i=0;i<n;i++)
        for(j=0;j<n;j++){
            M[i][j]=0;
        }
    for(i=0;i<n;i++){
        scanf("%d %d",&u,&k);
        u--;
        for(j=0;j<k;j++){
            scanf("%d",&v);
            v--;
            M[u][v]=1;
        }


    }
    bfs(0);
}

C++: #include<iostream>
#include<queue>
using namespace std;
void debug1();
int n, gragh[110][110] = {}, d[110] = {};
queue<int> q;

int main() {
	cin >> n;

	//inicialize
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= n; j++) {
			gragh[i][j] = -1;
		}
	}
	//input
	for (int i = 0; i < n; i++) {
		int u,k;
		cin >> u >> k;
		for (int j = 0; j < k; j++) {
			int t;
			cin >> t;
			gragh[u][t] = 1;
		}
	}
	debug1();
	//search
	d[1] = 0;
	q.push(1);
	while (!q.empty()) {
		int cur = q.front();
		q.pop();
		cerr << "visiting " << cur << " Distance: " << d[cur] << endl;
		for (int i = 1; i <= n; i++) {
			if (d[i] == 0 && gragh[cur][i] == 1) {
				d[i] = d[cur] + 1;
				q.push(i);
			}
		}
	}
	//output
	for (int i = 1; i <= n; i++) {
		cout << i << " " << d[i] << endl;
	}
	return 0;
}

void debug1() {
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= n; j++) {
			cerr << gragh[i][j] << " " ;
		}
		cerr << endl;
	}
}