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 <cstdio>
#include <queue>
#include <vector>

int main()
{
  int n;
  scanf("%d", &n);

  std::vector<std::vector<int>> graph;
  graph.resize(n);
  for (int i = 0; i < n; ++i)
  {
    int u, k, v;
    scanf("%d%d", &u, &k);
    for (int j = 0; j < k; ++j)
    {
      scanf("%d", &v);
      graph[u - 1].push_back(v - 1);
    }
  }

  std::queue<int> vertex;
  vertex.push(0);
  int current_distance = 0;

  int distances[100];
  for (int i = 0; i < 100; ++i)
    distances[i] = -1;

  while (vertex.size() > 0)
  {
    int s = vertex.size();

    // Loop for current depth
    for (int i = 0; i < s; ++i)
    {
      int id = vertex.front();
      vertex.pop();

      if (distances[id] == -1)
        distances[id] = current_distance;

      std::vector<int>::const_iterator itr;
      for (itr = graph[id].begin(); itr != graph[id].end(); ++itr)
      {
        if (distances[*itr] == -1)
          vertex.push(*itr);
      }
    }

    ++current_distance;
  }

  for (int i = 0; i < n; ++i)
    printf("%d %d\n", i + 1, distances[i]);

  return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <stack>
#include <queue>
#include <vector>
#include <map>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>

using namespace std;

struct Node {
	int k, d, f;
	vector<int> v;
};

#define MAX_N 100

Node node[MAX_N + 1];

int main() {
	int n;
	cin >> n;
	for (int i = 0; i < n; ++i) {
		int u;
		cin >> u;
		cin >> node[u].k;
		for (int j = 0; j < node[u].k; ++j) {
			int v;
			cin >> v;
			node[u].v.push_back(v);
		}
		node[u].d = -1;
	}
	queue<int> q;
	node[1].d = 0;
	q.push(1);
	while(!q.empty()) {
		int u = q.front(); q.pop();
		for (int i = 0; i < node[u].k; ++i) {
			int v = node[u].v[i];
			if (node[v].d == -1) {
				node[v].d = node[u].d + 1;
				q.push(v);
			}
		}
	}
	for (int i = 1; i <= n; ++i)
		cout << i << " " << node[i].d << endl;
	return 0;
}

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

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

  StDist(int nDist) : m_nDist(nDist), m_nMeTo(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_nMeTo)  continue; 

    rvoDist[nx].m_nMeTo = 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;

        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 <stdio.h>

int main (){

}

C++: #include <iostream>
#include <queue>
#define MAX 100
#define INF 2000000
#define WHITE 0
#define GRAY 1
#define BLACK 2

using namespace std;

int n;
int color[MAX+1];
int m[MAX+1][MAX+1];
int d[MAX+1];

void bfs(int s){
    queue<int> q;
    int u, v;
    for(u = 1; u <= n; u++){
        color[u] = WHITE;
        d[u] = INF;
    }
    color[s] = GRAY;
    d[s] = 0;
    q.push(s);
    while(!q.empty()){
        u = q.front();
        q.pop();
        for(v = 1; v <= n; v++){
            if(m[u][v] == 0 || d[v] != INF) continue;
            if(color[v] == WHITE){
                color[v] = GRAY;
                d[v] = d[u] + 1;
                q.push(v);
            }
        }
        color[u] = BLACK;
    }
}

int main(){
    int k, u, v, i, j;
    
    cin >> n;

    for(i = 1; i <= n; i++){
        for(j = 1; j <= n; j++) m[i][j] = 0;
    }

    for(i = 1; i <= n; i++){
        cin >> u >> k;
        for(j = 1; j <= k; j++){
            cin >> v;
            m[u][v] = 1;
        }
    }

    bfs(1);
    
    for(i = 1; i <= n; i++){
        cout << i << " ";
        if(d[i] == INF) cout << -1 << endl;
        else cout << d[i] << endl;
    }
    
    return 0;
}