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<algorithm>
#include<vector>
#include<cassert>
#include<cstdio>
#include<queue>

using namespace std;

int N, G[100][100], V[100], D[100];//G:２頂点,V:次数,D:距離

void bfs(int src){
	queue<int> Q;
	Q.push(src);
	fill(D, D + N, -1);
	D[src] = 0;
	while (!Q.empty()){
		int cur = Q.front();
		Q.pop();
		for (int k = 0; k < N; k++){
			if (G[cur][k] == 1 && D[k] == -1){
				D[k] = D[cur] + 1;
				Q.push(k);
			}
		}
	}
	for (int l = 0; l < N; l++){
		cerr << l + 1 << " " << D[l] << endl;
	}
}

int main(){
	scanf_s("%d", &N);
	int id, c;
	for (int i = 0; i < N; i++){
		scanf_s("%d", &id); id--;//配列は0から始まるので、頂点番号を-1して考える。
		scanf_s("%d", V + id);
		for (int j = 0; j < V[id]; j++){
			scanf_s("%d", &c); c--;//配列は0から始まるので、頂点番号を-1して考える。
			G[id][c] = 1;
		}
	}//データの読み込み完了。
	bfs(0);
}

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

int n;
vector<int> G[100];
int d[100];

int main() {
	int i;
	cin >> n;
	for ( i = 0; i < n; i++) {
		int u, k, v;
		cin >> u >> k;
		for( i = 0; i < k; i++) cin >> v, G[u - 1].push_back(v - 1);
	}
	for (i = 0; i < 100; i++) d[i] = -1;

	queue<int> q;
	q.push(0);
	d[0] = 0;
	while (!q.empty()) {
		int v = q.front(); q.pop();
		for (int i = 0; i < G[v].size(); i++) {
			int x = G[v][i];
			if (d[x] == -1) {
				d[x] = d[v] + 1;
				q.push(x);
			}
		}
	}
	for (i = 0; i < n; i++) cout << i + 1 << " " << d[i] << endl;

}

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

using namespace std;

const int N = 100;
int n;
int M[N][N], color[N], d[N];

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

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

using namespace std;

int n;
int vertex[101];
int graph[101][101];
int dis[101];

queue<int> Q;

int main() {
	cin >> n;
	int k,d;
	for (int i = 1; i <= n; ++i) {
		for (int j = 1; j <= n; ++j) {
			graph[i][j] = -1;
		}
		dis[i] = -1;
	}


	for (int i = 1; i <= n; ++i) {
		cin >> vertex[i] >> k;
		for (int j = 0; j < k; ++j) {
			cin >> d;
			graph[i][d] = 1;
		}
	}

	Q.push(1);
	dis[1] = 0;

	while (!Q.empty()) {
		k = Q.front();
		Q.pop();
		for (int i = 1; i <= n; ++i) {
			if (graph[k][i] == 1 && dis[i] == -1) {
				Q.push(i);
				dis[i] = dis[k]+1;
			}
		}
	}
	for (int i = 1; i <= n; ++i) {
		cout << i << ' ' << dis[i] << endl;
	}
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
struct cww{cww(){ios::sync_with_stdio(false);cin.tie(0);}}star;
#define P(x) cout << (x) << endl
#define p(x) cout << (x)
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define vv(type, c, m, n, i) vector<vector<type>> c(m, vector<type>(n, i));
#define rep(i,a,n) for(int i=(a), i##_len=(n); i<i##_len; ++i)
#define rrep(i,a,n) for(int i=(a), i##_len=(n); i>i##_len; --i)
#define len(x) ((int)(x).size())
#define mp make_pair
#define eb emplace_back
typedef long long ll;
typedef vector<int> vi;
typedef vector<double> vd;
typedef vector<long long> vll;
typedef vector<string> vs;
typedef vector<bool> vb;
constexpr int MAX = 101;
vi M(MAX, -1);
int main() {
	int n; cin >> n;
	M[1] = 0;
	deque<pair<int, int>> dq;
	int u, k, v;
	rep(i, 0, n) {
		cin >> u >> k;
		rep(j, 0, k) {
			cin >> v;
			if(u == 1) M[v] = 1;
			else dq.eb(mp(u, v));
		}
	}
	while(!dq.empty()) {
		tie(u, v) = dq.front(); dq.pop_front();
		if(M[u] == -1) dq.eb(mp(u, v));
		else if(M[v] == -1 || M[v] > M[u] + 1) M[v] = M[u] + 1;
	}
	rep(i, 1, n + 1) {
		cout << i << " " << M[i] << endl;
	}
	return 0;
}

C++: #include<cstdio>
#include<queue>
#define MAX 100
#define INFTY -1

using namespace std;
queue<int> Q;
int d[MAX];
int A[MAX][MAX]={0};
int n;

void bfs(int u)
{
	Q.push(u);
	d[u] = 0;

	while(!Q.empty())
	{
		int v = Q.front();
		Q.pop();
		for(int i=0; i<n; i++)
		{
			if(A[v][i] == 1)
			{
				if(d[i] == INFTY)
				{
					Q.push(i);
					d[i] = d[v] + 1;
					//printf("%d %d\n",v+1,d[v]);
				}
			}
		}
	}
}

int main()
{
	int u,k,v;
	scanf("%d", &n);
	for(int i=0; i<n; i++)
	{
		scanf("%d%d", &u, &k);
		u -= 1;
		for(int j=0; j<k; j++)
		{
			scanf("%d", &v);
			v -= 1;
			A[u][v] = 1;
		}
		d[u] = -1;
	}
	
	bfs(0);

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

	return 0;
}