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<iostream>
#include<cstdio>
#include<queue>
using namespace std;
const int INF=(1<<21);
int n,M[101][101];
int d[101]; //最短距離を記録(到達不可な時はINF)
void bfs(int s){
  queue<int>q;
  q.push(s);//始点sをいれる(訪問)
  for(int i=0;i<n;i++) d[i]=INF;
  d[s]=0;
  while(!q.empty()){
    int u=q.front();
    q.pop();
    for(int v=0;v<n;v++){
      if(M[u][v]==0) continue; //辺がない
      if(d[v]!=INF) continue; //訪問したことがある
      d[v]=d[u]+1; //vは未訪問の頂点であり、隣接しているためd[u]に1を足す
      q.push(v); //vを始点に
    }
  }
  for(int i=0;i<n;i++){
    cout<<i+1<<" "<<( (d[i]==INF)?(-1):d[i] )<<endl;
  } //到達不可能か
}
int main(){
  int u,k,v;
  scanf("%d",&n);
  for(int i=0;i<n;i++){
    scanf("%d%d",&u,&k);
    u--;
    for(int j=0;j<k;j++){
      scanf("%d",&v);
      v--;
      M[u][v]=1;
    }
  }
  bfs(0);
  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

using ll = long long;
#define REP(i, n) for(int (i)=0; (i)< (n); ++i)
#define REPR(i, n) for(int (i)=(n); (i)>=0; --i)
#define FOR(i, n, m) for(int (i)=(n); (i)<(m); ++i)


int main(){
  int n;
  cin >> n;
  vector<vector<int>> g(n);
  REP(i, n){
    int id, k;
    cin >> id >> k;
    g[i].resize(k);
    REP(j, k){
      int v;
      cin >> v;
      v--;
      g[i].push_back(v);
    }
  }
  vector<int> dist(n, -1);
  dist[0] = 0;
  queue<pair<int, int>> que;
  que.push({0,0});
  while(!que.empty()){
    int v, d;
    tie(v, d) = que.front();que.pop();
    REP(i, g[v].size()){
      int nv = g[v][i];
      if(dist[nv] != -1) continue;
      dist[nv] = d + 1;
      que.push({nv, d+1});
    }
  }
  REP(i, n){
    cout << i+1 << " " << dist[i] << endl;
  }
  return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <vector>
#include <deque>
#include <queue>
#include <list>
#include <stack>
#include <string>
#include <tuple>
#include <functional>
#include <numeric>
#include <cmath>
#include <iomanip>
#include <map>
#include <random>
#include <cstdlib>
#define Loop(i, n) for(int i = 0; i < (int)n; i++)
#define Loop1(i, n) for(int i = 1; i <= (int)n; i++)
#define Loopr(i, n) for(int i = (int)n - 1; i >= 0; i--)
#define Loopr1(i, n) for(int i = (int)n; i >= 1; i--)
using namespace std;
typedef long long int ll;

vector<int> V[105];
queue<int> Q;
vector<int> color(105, 1), d(105, 0);

int main() {
	int n;
	cin >> n;
	Loop(i, n) {
		int u, k;
		cin >> u >> k;
		Loop(j, k) {
			int v;
			cin >> v;
			V[u].push_back(v);
		}
	}
	//
	Q.push(1);
	color[1] = 2;
	while (Q.size() > 0) {
		int u = Q.front();
		Q.pop();
		Loop(i, V[u].size()) {
			if (color[V[u][i]] == 1) {
				Q.push(V[u][i]);
				color[V[u][i]] = 2;
				d[V[u][i]] = d[u] + 1;
			}
		}
	}
	Loop1(i, n) {
		cout << i << " " << d[i] << endl;
	}
	return 0;
}

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

int n;
vector< vector<int> > G;
vector<int> color;
vector<int> dis;

void Bfs(int start) {
  queue<int> q;
  q.push(start);
  color[start]++;
  dis[start] = 0;

  while (q.empty() == false) {
    int u = q.front();
    q.pop();
    for (int v = 0; v < n; v++) {
      if (G[u][v] == 1 && color[v] == 0) {
        color[v]++;
        dis[v] = dis[u] + 1;
        q.push(v);
      }
    }
    color[u]++;
  }
}

int main() {
  cin >> n;
  G.resize(n, vector<int>(n));
  color.resize(n);
  dis.resize(n, -1);
  for (int i = 0; i < n; i++) {
    int u, k;
    cin >> u >> k;
    u--;
    for (int j = 0; j < k; j++) {
      int v;
      cin >> v;
      v--;
      G[u][v]++;
    }
  }

  Bfs(0);

  for (int i = 0; i < n; i++) cout << i + 1 << " " << dis[i] << endl;
}

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;
}